SOLUTION: Susan has a number of dimes and quarters in her pocket. She has a total of 84 coins, and the total dollar value of all dimes and quarters is $15. Write two equations, using

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Question 343930: Susan has a number of dimes and quarters in her pocket.
She has a total of 84 coins, and the total dollar value of all dimes and quarters is $15.
Write two equations, using variables �d� and �q� to represent the number of dimes and quarters Susan has.
Solve those two equations using either the substitution or elimination method to find how many dimes and how many quarters she has.
Found 3 solutions by Fombitz, stanbon, josmiceli:
Answer by Fombitz(32388)   (Show Source):
You can put this solution on YOUR website!
Total number of coins
1.
Total value of coins (in cents)

2.
Multiply eq. 1 by (-2) and add it to eq. 2,

Then from eq. 1,

.
.
.
Forty dimes and forty four quarters.

Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website!
She has a total of 84 coins, and the total dollar value of all dimes and quarters is $15.
Write two equations, using variables �d� and �q� to represent the number of dimes and quarters Susan has.
Solve those two equations using either the substitution or elimination method to find how many dimes and how many quarters she has.
------------------
Quantity Eq.:::: d + q = 84
Value Eq::::::: 10d+25q = 1500 cents
------------------------------------------
Multiply thru the 1st by 10.
10d + 10q = 10*84
10d + 25q = 1500
------------------
Subtract 1st from 2nd and solve for "q":
15q = 660
q = 44 (# of quarters)
--------------------------------
Since d+q = 84, d = 40 (# of dimes)
======================================
Cheers,
Stan H.
========

Answer by josmiceli(19441)   (Show Source):
You can put this solution on YOUR website!
given:
(1)
(2) (in cents)
Multiply both sides of (1) by
and subtract (1) from (2)
(2)
(1)

And, from (1),
(1)

She has 40 dimes and 44 quarters
check answer:
(2)
(2)

OK