Every evening Jenna emptied her pocket and put your change in a jar at the end of the week she counts her money one week she had

Question

4 years ago

15

40 coins all of the them dimes and quarters then she added them up she had a total of $7.75

1 answer:

Lelu [443] · Answer 1 · 2021-12-03T12:13:41+03:00

Answer:

Jenna had 25 quarters and 15 dimes.

Step-by-step explanation:

Let Q = the number of quarters and D = the number of dimes.

Then:

1) Q+D = 40 "One week she had 40 coins, all of them dimes and quarters...."

2) 0.25Q+0.1D = $7.75 "...she had a total of $7.75."

Rewrite equation 1) as: D = 40-Q and substitute into equation 2).

2a) 0.25Q+0.1(40-Q) = 7.75 Simplify the left side.

2b) 0.25Q+4-0.1Q = $7.75 Subtract 4 from both sides.

2c) 0.25Q-0.1Q = 3.75 Combine the like-terms on the left side.

2d) 0.15Q = 7.75 Divide both sides by 0.15

2e) Q = 25 and:

D = 40-Q

D = 40-25

D = 15

Jenna had 25 quarters and 15 dimes.