Question

Deangelo has $7 worth of dimes and quarters in a jar. He has 7 more quarters than dimes. How many of each coin does he have? Enter your answers in the boxes. _dimes and _ quarters

Answer 1

0.10d + 0.25q = 7
q = d + 7

0.10d + 0.25(d + 7) = 7
0.10d + 0.25d + 1.75 = 7
0.35d = 7 - 1.75
0.35d = 5.25
d = 5.25 / 0.35
d = 15 <=== there are 15 dimes

q = d + 7
q = 15 + 7
q = 22 <== there are 22 quarters

Answer 2

There are 15 dimes and 22 quarters in the jar.

Explanation:

Deangelo has $7 worth of dimes and quarters in a jar.

Let he has d number of dimes and q number of quarters in a jar.

0.10d + 0.25q = 7 -------(1)

He has 7 more quarters than dimes.

q = d + 7 -------(2)

We replace the value of y from equation 2 in the equation 1

0.10d + 0.25(d + 7) = 7

0.10d + 0.25d + 1.75 = 7

0.35d = 7 - 1.75

0.35d = 5.25

d =
`(5.25)/(0.35)=15` dimes

Now we put this value in the equation number 2

q = 15 + 7 = 22

Therefore, number of dimes and quarters are 15 and 22 respectively.