A hot dog and a soda cost $1.10. The hot dog is a dollar more than the soda, how much is the soda?
A nickel.
Wait…what are the taxes? 
.5
Ten cents.
ETA: Math fail. I was never good at this stuff. 5 cents?
This must have been in the old days where a soda cost a nickel. But then the hot dog would only cost a nickel then too. Everything cost a nickel in the old days, it was the only unit of currency. So the question has no reality based answer, just a theoretical one.
2 dollars. There’s no way a nickel’s worth of soda will be enough.
Wait…is this in New York and the soda is over 16 oz? 'cause that’s illegal territory, bud!
All right, help me out here… how does 1.10 - 1.00 = .05? Is there some new rule of basic arithmetic that’s been discovered since I was in gradeschool?
The soda is five cents, the hot dog is 1.05 dollars - therefore, the hot dog is one dollar more than the soda if the soda is five cents.
Caveat: I"m no math genius. If I’m wrong, well, it won’t be the first time. 
I must be dumb too, because I instantly said “ten cents.”
As in, 50 cents??
Man, you guys got me totally confused.
5 copper disks.
Uh…yeah typo, I was going for .05
nm
.5 cents.
If it makes folks feel any better, half of students at Harvard, Princeton and MIT got this question wrong when asked. Whether you get it right or not is not really correlated with your intelligence.
If the hot dog costs a dollar more than the soda, and if the soda is 5 cents, then
.05 + 1.00 = 1.05.
The cost of the soda and hot dog together:
.05 + 1.05 = 1.10.
I knew MIT wasn’t worth my time.
A hapenny?
It is all in the wording.
Obviously if you choose $1.00 for the hot dog and $0.10 for the drink, the difference is $0.90.
So, to fulfill the requirements of this little gem, you have to say $1.05 for the hot dog and $0.05 for the drink. That makes the difference equal to $1.00.
Shall I draw a diagram?