Jessica has $2.15 in dimes and quarters. She has 3 less dimes than quarters. How many of each does she have?

Question

pleae help

Answer 1

If she has $2.15 in quarters and dimes, then we can come up with this equation:

 

0.25q + 0.10d = 2.15

 

Where q is the number of quarters she has and d is the number of dimes.

 

We can also come up with:

 

d = q - 3

 

since she has 3 less dimes than quarters (so the number of dimes she has is 3 less than the number of quarters).

 

We can now plug in q - 3 for d in the first equation:

 

0.25q - 0.10(q - 3) = 2.15

 

and then solve for q:

 

0.25q - 0.10q - 0.3 = 2.15

0.35q = 2.45

q = 7

 

So the number of quarters she has is 7. Since she has 3 less dimes than quarters, she has 7 - 3 = 4 dimes. And is we want to check our work, we can plug in the numbers we have solved for into the first equation:

 

0.25(7) + 0.10(4)

1.75 + 0.40

2.15