Question

Wilma has 21 coins in her pocket made up of dimes and quarters. If the total value of the coins is $3.45, how many of each coin does she have?

Answer 1

x = 12

y = 9

12 coins of dimes

9 coins of quartes

Explanation:

x ---> coins of dimes

y ---> coins of quartes

x + y = 21

0.1x + 0.25y = 3.45 * 100

x + y = 21 L1

10x + 25y = 345 L2

x = 21 - y

Reemplace in L2

10(21 - y) + 25y = 345

210 - 10y + 25y = 345

15y = 345 - 210

15y = 135

y = 9

x = 21 - y

x = 21 - 9

x = 12