Question

A piggy bank contains $5.45 in dimes and quarters. If the bank contains 29 coins, how many quarters are in the bank?

12 quarters
17 quarters
21 quarters

Answer 1

.1x + .25y = 5.45
x + y = 29

Multiply the second equation by -.1
.1x + .25y = 5.45
-.1x - .1y = -2.9 Now add the equations together, the x's will cancel.
------------------------
.15y = 2.55 Divide both sides by .15
y = 17
29 - 17 = 12
12 dimes and 17 quarters

CHECK
12 * .1 + 17*.25 = $5.45

Answer 2

there are 12 dimes in there
and 17 quaters