SOLUTION: Mackenzie has 19 coins in her pocket. They are all either dimes or quarters, totaling $3.40.
How many coins are quarters?
Solve the word problem by creating a system of equat
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-> SOLUTION: Mackenzie has 19 coins in her pocket. They are all either dimes or quarters, totaling $3.40.
How many coins are quarters?
Solve the word problem by creating a system of equat
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Question 924248: Mackenzie has 19 coins in her pocket. They are all either dimes or quarters, totaling $3.40.
How many coins are quarters?
Solve the word problem by creating a system of equations. Use substitution to find the solution.
Let the number of dimes be D
Let the number of dimes be Q
Value Value
Type Number of of
of of EACH ALL
coin coins coin coins
-------------------------------------------
DIMES D $0.10 $0.10D
QUARTERS Q $0.25 $0.25Q
-------------------------------------------
TOTALS 19 ----- $3.40
The equations comes from the "Number of coins" column
and the "Value of ALL coins" column:
Get rid of decimals in the second by multiplying
every term by 100
10D + 25Q = 340
Solve the first for D
D+Q=19
D=19-Q
Substitute in
10D + 25Q = 340
10(19-Q) + 25Q = 340
190-10Q + 25Q = 340
190+15Q = 340
15Q = 150
Q = 10 quarters
D = 19-Q = 19-10 = 9 dimes
Edwin