SOLUTION: COIN PURSE CONTAINS A MIXTURE OF 15 COINS IN DIMES AND QUARTERS. THE COINS HAVE A TOTAL VALUE OF $3.30. DETERMINE THE NUMBER OF DIMES AND THE NUMBER OF QUARTERS IN THE PURSE.

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: COIN PURSE CONTAINS A MIXTURE OF 15 COINS IN DIMES AND QUARTERS. THE COINS HAVE A TOTAL VALUE OF $3.30. DETERMINE THE NUMBER OF DIMES AND THE NUMBER OF QUARTERS IN THE PURSE.      Log On


   

Question 164537: COIN PURSE CONTAINS A MIXTURE OF 15 COINS IN DIMES AND QUARTERS. THE COINS HAVE A TOTAL VALUE OF $3.30. DETERMINE THE NUMBER OF DIMES AND THE NUMBER OF QUARTERS IN THE PURSE.
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!

D%2BQ=15coins --------------------> EQN 1
Also,
0.10D%2B0.25Q=3.30 ---------------> EQN 2
In EQN 1, we get,
D=15-Q -------------------------> EQN 3
Subst, EQN 3 in EQN 2:
0.10%2815-Q%29%2B0.25Q=3.30
1.50-0.10Q%2B0.25Q=3.30
0.15Q=3.30-1.50=1.80
cross%280.15%29Q%2Fcross%280.15%29=cross%281.80%2912%2Fcross%280.15%29
highlight%28Q=12coins%29
Via EQN 3,
highlight%28D=15-12=3coins%29
In doubt? Go back EQN 2,
0.10%283%29%2B0.25%2812%29=3.30
0.30%2B3=3.30
3.30=3.30
Thank you,
Jojo