SOLUTION: every evening jenna empties out her pockets and puts her change in a jar. at the end of the week she counts her money. one week she had 40 coins, all of them dimes and quaters. whe

Question 204097: every evening jenna empties out her pockets and puts her change in a jar. at the end of the week she counts her money. one week she had 40 coins, all of them dimes and quaters. when she added them up she had a total of &7.75.
how many dimes did jenna have??
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
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.
RELATED QUESTIONS
Every evening Jenna empties her pockets and puts her change in a jar. At the end of the... (answered by josgarithmetic)

every evening jenna empties her pockets and puts her change in a jar. at the end of the... (answered by solver91311)

Every evening Jenna empties her pockets. And puts her change in a jar at the end of the... (answered by stanbon)

every evening jenna empties her pockets and puts her change in the jar. At the end of the (answered by Alan3354)

Riley receives money for her birthday this week. She spent 1/3 of her birthday money on... (answered by josmiceli)

A patient�s dosage of medication is decreased 25 milligrams per day for one week. What is (answered by Alan3354)

Jen has $12 in her wallet and begins saving money every day. At the end of the tenth day, (answered by Boreal)

at the beginning of summer molly decided to add a little monet into her savings account... (answered by TimothyLamb)

A waitress waited on 20 tables one evening. after sharing 13.00 of her tip money with the (answered by solver91311)