Question

I have 31 stamps total. I have 4 more 1-cent stamps than 8-cent stamps and twice as many one cent stamps as 12 cent stamps. If my stamps are worth $1.78 altogether how many one cent stamps do I have?

Answer 1

Answer: 14 1-cent stamps (in case anyone else still needs)

Explanation:

1-cent stamps=x

8-cent stamps=x-4

12-cent stamp=.5x

x+x-4+.5x=31

2.5x-4=31

2.5x=35

x=14

You can use the $1.78 to double check:

(1*14)+(8*10)+(12*7)

14+80+84=178 cents (or $1.78)