Question

Tom sells baseball cards at 10 for 35 cents. Is that a better deal than 12 for 40 cents?

Answer 1

1 case
35c : 10 = 3,5c 
2 case
40c : 12 = 3,(3)c

3,(3)c < 3,5c

Anwers
First option is a better deal than second version.

Answer 2

For either one of the deals, just find what one card equals and times it by how many cards the other equation has.

e.g. 0.35 cents divide by 10 = 0.035. And now, you times it by 12 since the other deal is 12 cards for 40 cents.

0.035 x 12 = 0.48

So, 10 cards for 35 cents is not the better deal.