Question
George has 21 coins with a total value of $12.75. He knows he only has quarters and dollar coins in his pocket. How many coins of each type does he have? Create a system to solve.
Answers
Reiny
number of $1 coins --- x
number of quarters ---- y
x + y = 21
100x + 25y = 1275 --> 4x + y = 51
subtract them:
3x = 30
x = 10
then y = 11
He has 10 dollar coins and 11 quarters
check
value: 100(10) + 25(11) = 1275 cents = $12.75
number of quarters ---- y
x + y = 21
100x + 25y = 1275 --> 4x + y = 51
subtract them:
3x = 30
x = 10
then y = 11
He has 10 dollar coins and 11 quarters
check
value: 100(10) + 25(11) = 1275 cents = $12.75