# Grade 7-12 math contest sample problems **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [February 27, 2019, 8:30pm UTC](https://boards.straightdope.com/t/grade-7-12-math-contest-sample-problems/830308 "2019-02-27T20:30:42Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Hampshire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hampshire/32/4887_2.png) [@Hampshire](https://boards.straightdope.com/u/Hampshire)\ **Post date:** [February 27, 2019, 8:30pm UTC](https://boards.straightdope.com/t/grade-7-12-math-contest-sample-problems/830308/1 "2019-02-27T20:30:42Z")
My son is going to a math contest put on by a state college and the flyer had a few sample problems but no answers. Just for fun I tried them am not that confident in my answer for the third one. -Grade 7 & 8: There are 10 red, 5 green, and 7 yellow balls in a box. What is the minimum number of balls to be taken out (without replacement) in order to guarantee that at least one green and at least one yellow ball will be taken out? -Grade 9 & 10: Five million dollars in $20 bills weigh about 550 pounds. What is a good estimate for the weight of twenty million dollars in $100 bills? -Grade 11 & 12: The longest side of a certain triangle is 4 cm. less than the sum of the other two sides. Twice the shortest side is 9 cm less than the longest side. What is the absolute difference between the middle-sized side and the shortest side? 18, worst case scenario would be 10 red 7 yellow 1 green picked. 440 pounds, assuming each bill weighs .0022 pounds regardless of denomination 13, based on L(long),M(middle),S(short) L=M+S-4 and L=2S+9 ---
**Author:** ![StGermain](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/stgermain/32/2868_2.png) [@StGermain](https://boards.straightdope.com/u/StGermain)\ **Post date:** [February 27, 2019, 9:09pm UTC](https://boards.straightdope.com/t/grade-7-12-math-contest-sample-problems/830308/2 "2019-02-27T21:09:44Z")
Nevermind, you’re right. StG ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [February 27, 2019, 9:17pm UTC](https://boards.straightdope.com/t/grade-7-12-math-contest-sample-problems/830308/3 "2019-02-27T21:17:37Z")
Yep, I got the same answers as you for all three. ---
**Author:** ![Knowed\_Out](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/knowed_out/32/7380_2.png) [@Knowed\_Out](https://boards.straightdope.com/u/Knowed_Out)\ **Post date:** [February 28, 2019, 8:44pm UTC](https://boards.straightdope.com/t/grade-7-12-math-contest-sample-problems/830308/4 "2019-02-28T20:44:55Z")
ditto for all three