Answers: 85 dimes and 72 quarters
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Work Shown:
x = number of dimes
y = number of quarters
x+y = 157 coins total
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$26.50 = 2650 cents
1 dime = 10 cents
x dimes = 10x cents
1 quarter = 25 cents
y quarters = 25y cents
total value = 10x+25y = 2650 cents
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We have this system of equations
x+y = 157
10x+25y = 2650
Let's solve for y in the first equation
x+y = 157
y = 157-x
Then plug this into the second equation and solve for x.
10x+25y = 2650
10x+25(157-x) = 2650
10x+25(157)+25(-x) = 2650
10x+3925-25x = 2650
-15x+3925 = 2650
-15x = 2650-3925
-15x = -1275
x = -1275/(-15)
x = 85 is the number of dimes
Then use this to find the value of y
y = 157-x
y = 157-85
y = 72 is the number of quarters
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Check:
85 dimes + 72 quarters = 157 coins total
85 dimes = 85*10 = 850 cents
72 quarters = 72*25 = 1800 cents
850 cents + 1800 cents = 2650 cents = $26.50
This confirms the answers.