# A logic puzzle about family **URL:** \ **Category:** Thread Games\ **Created:** [May 19, 2021, 1:17pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463 "2021-05-19T13:17:38Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![turtlescanfly](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@turtlescanfly](https://boards.straightdope.com/u/turtlescanfly)\ **Post date:** [May 19, 2021, 1:17pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/1 "2021-05-19T13:17:38Z")
So I was thinking about my own blended family the other day I somehow got to thinking it might make an interesting logic puzzle, for those that like that sort of thing. Given the following facts about my family, can you determine how many kids I have? By my kids I mean to include my own biological children as well as stepchildren. If half, full, or step status is not specified, assume that any of the three fit the required criteria. Also assume that when I say " at least" that if I was able to say I higher number I would. 1. All of my kids have at least 2 half-siblings. 2. All of my kids have at least 3 step-siblings, except the youngest who has none. 3. There are an equal number of sons and daughters. 4. Each child has at least 2 brothers and 2 sisters. 5. I have been married twice and have at least two stepchildren from each wife. 6. None of my children has more than 4 brothers or 4 sisters. Can you correctly deduce how many children I have ( no guessing, actually deducing from the information provided ?). If not, what additional hints are required. ? P.S. I put this in GQ because it has a factual answer, but if mods feel it’s a better fit for Thread Games, IMHO, or MPSIMS, then so be it. ---
**Author:** ![CardboardBoxx](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardboardboxx/32/7079_2.png) [@CardboardBoxx](https://boards.straightdope.com/u/CardboardBoxx)\ **Post date:** [May 19, 2021, 1:50pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/2 "2021-05-19T13:50:16Z")
never mind, misread something. ---
**Author:** ![Dung\_Beetle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dung_beetle/32/7945_2.png) [@Dung\_Beetle](https://boards.straightdope.com/u/Dung_Beetle)\ **Post date:** [May 19, 2021, 1:51pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/3 "2021-05-19T13:51:41Z")
I used to love doing those logic puzzle magazines, with the handy chart to fill in. I don’t suppose you could provide me one of those? 😉 My answer thus far would be 6 or 8, because clue 3 means it’s an even number. Clue 6, though…it doesn’t say anyone _necessarily_ has four siblings. ---
**Author:** ![turtlescanfly](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@turtlescanfly](https://boards.straightdope.com/u/turtlescanfly)\ **Post date:** [May 19, 2021, 2:04pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/4 "2021-05-19T14:04:20Z")
I wouldn’t even begin to know how to set up a chart like that! It seems to me now that the combination of clues 3 and 6 pretty much definitively give away the total number of kids, regardless of the other clues. ---
**Author:** ![solost](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/solost/32/11776_2.png) [@solost](https://boards.straightdope.com/u/solost)\ **Post date:** [May 19, 2021, 2:06pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/5 "2021-05-19T14:06:55Z")
Is the answer “The Brady Bunch”? 🙂 ---
**Author:** ![turtlescanfly](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@turtlescanfly](https://boards.straightdope.com/u/turtlescanfly)\ **Post date:** [May 19, 2021, 2:11pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/6 "2021-05-19T14:11:14Z")
I dont think any of the kids in the Brady Bunch had any half siblings. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [May 19, 2021, 2:12pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/7 "2021-05-19T14:12:55Z")
How are 2. and 5. compatible? Are you splitting the total children into family groups somehow so that the youngest isn’t a step-sibling to your step-children from your first marriage? ---
**Author:** ![Dung\_Beetle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dung_beetle/32/7945_2.png) [@Dung\_Beetle](https://boards.straightdope.com/u/Dung_Beetle)\ **Post date:** [May 19, 2021, 2:16pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/8 "2021-05-19T14:16:01Z")
🤦‍♀️ Good point. ---
**Author:** ![solost](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/solost/32/11776_2.png) [@solost](https://boards.straightdope.com/u/solost)\ **Post date:** [May 19, 2021, 2:16pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/9 "2021-05-19T14:16:52Z")
> [@turtlescanfly](#): > > I dont think any of the kids in the Brady Bunch had any half siblings. Mike Brady was a widower, but Carol Brady, I believe, was a divorcee. Who knows what she got up to before she married Mike, so her three girls could’ve had up to 3 baby daddys. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 19, 2021, 2:25pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/10 "2021-05-19T14:25:54Z")
Or what Mike’s wife was doing with Carol’s husband. ---
**Author:** ![solost](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/solost/32/11776_2.png) [@solost](https://boards.straightdope.com/u/solost)\ **Post date:** [May 19, 2021, 2:31pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/11 "2021-05-19T14:31:34Z")
Right. It was the 70s after all, there may have been some key parties involved. In fact, maybe that’s how Mike and Carol first met, meaning one or two of the daughters could actually be his, further complicating matters. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 19, 2021, 2:35pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/12 "2021-05-19T14:35:35Z")
I think that kid Bobby actually had blond hair but they dyed it dark. Undoubtedly to avoid suspicion. ---
**Author:** ![TokyoBayer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tokyobayer/32/13989_2.png) [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)\ **Post date:** [May 19, 2021, 2:43pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/13 "2021-05-19T14:43:47Z")
> [@naita](#): > > How are 2. and 5. compatible? Are you splitting the total children into family groups somehow so that the youngest isn’t a step-sibling to your step-children from your first marriage? I got stuck on that one as well. ---
**Author:** ![turtlescanfly](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@turtlescanfly](https://boards.straightdope.com/u/turtlescanfly)\ **Post date:** [May 19, 2021, 3:25pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/14 "2021-05-19T15:25:01Z")
I suppose it depends on how you define it, but no me personally I would not consider my stepchildren from my first marriage to be step brother and sister to my daughter from my second marriage. Frankly surprised that anyone would, but it seems several of you here have commented on that. In other words, my stepson is not automatically a stepbrother to my biological daughter, in the same way that my cousin can have another cousin that is not my cousin. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 19, 2021, 3:40pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/15 "2021-05-19T15:40:09Z")
Carrie Fisher talked about these step- and half- relationships in her family. Her mother Debbie Reynolds was married three times, but had only two children of her own with Carrie’s father, Eddie Fisher. He was married five times and had 4 children of his own. One of his wives was Elizabeth Taylof who was married eight times. Given the broadest definition of ‘step-sibling’ there were a lot of them. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [May 19, 2021, 3:43pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/16 "2021-05-19T15:43:20Z")
> [@solost](#): > > Right. It was the 70s after all, there may have been some key parties involved. > > In fact, maybe that’s how Mike and Carol first met, meaning one or two of the daughters could actually be his, further complicating matters. Mike actually implies this once, when he suggests that one of the girl’s talents was inherited from his side of the family. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [May 19, 2021, 5:30pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/17 "2021-05-19T17:30:27Z")
> [@turtlescanfly](#): > > In other words, my stepson is not automatically a stepbrother to my biological daughter, in the same way that my cousin can have another cousin that is not my cousin. Sure, but the difference is that those “outer” cousins don’t have ancestors in common, which is how cousins are defined, while you are stepfather, or father to all those kids. Not saying your definition isn’t perfectly fine, but it seems logically inconsistent to still claim them as your stepchildren if your later children aren’t their stepsiblings. Anyway, with that clarification combined with each of the kids having supposedly a minimum of 3 step-siblings I’m abandoning this puzzle as too confusing. ---
**Author:** ![turtlescanfly](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@turtlescanfly](https://boards.straightdope.com/u/turtlescanfly)\ **Post date:** [May 20, 2021, 1:47am UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/18 "2021-05-20T01:47:07Z")
Sorry for the bad communication on my part. I suspected it might be confusing, I was looking for advice on how to make it less so. As well as logically consistent and solvable ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [May 20, 2021, 6:28pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/19 "2021-05-20T18:28:45Z")
I’m not a puzzle maker, though I like solving them occasionally, but I think it’s probably quite hard to give advice on making this puzzle easier without knowing the answer. Also I know I wrote I wouldn’t try, but I’m just in the mood to be nerd-sniped today. Solving puzzles is easier when the information is in the most useful order, so choosing the order is one way of adjusting the level of difficulty. So let me try to cherry pick information and see how far I get before I’m too confused to care to continue. You write that both of your wives had at least two children. I’m going to label the wives A and B and number the kids, so we have a minimum of A1, A2 B1, B2 Then there is your youngest having no step-siblings, I’ll label that child BT1 So we have A1, A2 B1, B2, BT1 And now things get messy due to who is a step-sibling to whom, so let’s do the half-siblings first. Presumably all children and siblings here are “your kids”, or things are not solvable at all I think. Not that they are now. For A1 and A2 to have two half siblings … wait, what if they are half siblings to each other? Let’s go with that for now. There is a child AT1. Now all the A children have two half siblings. That doesn’t give us enough step-siblings though. Let’s go with AT1 and AT2. A1, A2 AT1, AT2 B1, B2, BT1 That’s two half siblings for all the As and for BT1. But how does B1 and B2 get another half sibling without that one also having no step-siblings? Yeah, this is where I bow out without some clear information about how many family groups each child belongs in, and how many family groups there are. ---
**Author:** ![turtlescanfly](https://avatars.discourse-cdn.com/v4/letter/t/65b543/32.png) [@turtlescanfly](https://boards.straightdope.com/u/turtlescanfly)\ **Post date:** [May 20, 2021, 8:01pm UTC](https://boards.straightdope.com/t/a-logic-puzzle-about-family/942463/20 "2021-05-20T20:01:09Z")
I agree, constructing a puzzle is easier if you know the answer, so here it is. 2 step children from my first wife. Full siblings ( same mother and father) 3 biological children from my first wife. So they are half siblings with my first two stepchildren. 2 stepchildren from my second wife. They are half siblings to each other ( same mother/different father). Then one biological daughter with my second wife. She is half siblings with my bio children from my first wife but also to my stepchildren from my second wife. The tricky part of the puzzle I figured would be that no one would presume the possibility that the stepchildren from my second marriage were already half siblings to each other. Also, my bio children from my first marriage have step siblings from my first wife’s new husband, which may not occur to anyone but is not precluded from the clues, which is what allows them to have the minimum three each.