SOLUTION: At Scott's Laundromat, the washing machines accept only quarters and nickels. If Joe used 20 coins worth $2.60 to wash 4 loads, how many of each coin did he use? A. 7 quarter

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Question 939394: At Scott's Laundromat, the washing machines accept only quarters and nickels. If Joe used 20 coins worth $2.60 to wash 4 loads, how many of each coin did he use?
A. 7 quarters and 13 nickels
B. 6 quarters and 14 nickels
C. 8 quarters and 12 nickels
D. 9 quarters and 11 nickels
Answer by srinivas.g(540) About Me  (Show Source):
You can put this solution on YOUR website!
1 nickle = 0.05 dollars
1 quarter =0.25 dollars
let x be the no of nickles
let y be the no of quarters
total no of coins =20
x+y = 20..............eq(1)
total worth = $ 2.60
x*0.05+y*0.25 = $2.60 ..............eq(2)
Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
We'll use substitution. After moving 1*y to the right, we get:
1%2Ax+=+20+-+1%2Ay, or x+=+20%2F1+-+1%2Ay%2F1. Substitute that
into another equation:
0.05%2A%2820%2F1+-+1%2Ay%2F1%29+%2B+0.25%5Cy+=+2.6 and simplify: So, we know that y=8. Since x+=+20%2F1+-+1%2Ay%2F1, x=12.

Answer: system%28+x=12%2C+y=8+%29.

Result : nickles =12
quarters = 8
Option : C is the right choice