There is a jar containing 85 coins, all of which are either quarters or dimes. The total value of the coins is $13.00. How many of each coin are in the jar?

Answer 1

Hello Kimoya.

dimes equals 0.1 $

quarters equals 0.25$

lets say d represent # of dimes;

q represent # of quarters

d + q = 85

0.1d +0.25q = 13 to solve this system of equation; we can multiply second equation by 10 first;

d + 2.5q =130, we have d for both of the equations now we can multiply one of the equation to get -d

we can multiply first equation by -1, and we get

-d -q =-85, lets keep second equation and combine them

d +2.5q = 130

1.5q = 45; q =30

since d +q=85; d +30 =85; d = 55

hope that helps