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Use substitution to solve
Drew has a coin jar with a small collection of nickels and dimes. There are 148 coins in the jar.
They have a value of $13.20. How many nickels and dimes are in the jar?
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Let x be the number of nickels and y be the number of dimes.
Write the system of equations as you read the problem
x + y = 148 (1) (total coins)
5x + 10y = 1320 (2) (total cents)
From equation (1), express x = 148-y and substitute it into equation (2), replacing x there
5(148-y) + 10*y = 1320.
Simplify
5*148 - 5y + 10y = 1320
5y = 1320 - 5*148
5y = 580
y = 580/5 = 116.
So, there are 116 dimes.
From equation (1), the number of nickels is x = 148 - 116 = 32.
ANSWER. 32 nickels and 116 dimes.
CHECK. 32*5 + 116*10 = 1320 cents, in total. ! Correct !
Solved.
