Jayna has 8 dimes and quarters. if she has $1.10 in change, then how many of each coin does she have

Answer 1

D + Q = 8

So D = 8 - Q (quantity equation)

Easier to work with cents (no decimals)

10D + 25Q = 110 (value equation)

Substitute; 10(8 - Q) + 25Q = 110 Use distribution rule.

80 - 10Q + 25Q = 110

combine like terms: 15Q = 30; Q = 2

Then D = 6

Check: 6(10) + 2(25) = 60 + 50 = 110