If the total value is 7.60, how many dimes and how many quarters are there?

Question

A collection is f 43 coins consists of dimes and quarters. If the total value is 7.60, how many dimes and how many quarters are there?

Answer 1

d + q = 43 (number of dimes and quarters = 43)

.1d + .25q = 7.6 (the value of the coins = $7.60)

 

Let's try to solve via substitution:

d = 43 - q

 

.1(43 - q) + .25 q = 7.6

4.3 - .1q + .25q = 7.6

4.3 + .15q = 7.6

.15q = 3.3

Divide both sides by .15

q = 22

 

Now to solve for d:

d = 43 - 22

d = 21

 

Now to check:

.1 * 21 + .25 * 22 = 7.6

2.1 + 5.5 = 7.6

7.6 = 7.6