Valerie C. answered 09/01/12
Experienced College Educator with Math High School Teaching Credential
Let the number of Ben's stamps = X since the problem gives us that directly. Then since the problem gives the number of stamps for Andrew and Carl in term's of Ben's stamps we need to write equations using X which is the number of Ben's stamps.
For Andrew it says he has 86 more stamps than Ben so you get X + 86 for Andrew's stamps.
For Carl it says he has 156 more stamps than Ben so you get X + 156 for Carl's stamps.
The problem also says that together they have 776 stamps. I think this means that Ben + Andrew + Carl have that many stamps. if this is true then you can say: X + (X+86) + (X+156) = 776. Then you should be able to combine the X's and get 3X + 242 = 776 and solve for X. You should be able to solve for X now by subtracting 242 from both sides of the equals sign and get 3X = 534. If you then divide both sides by 3 to get X all by itself you get X = 178 stamps for Ben.