Doug C. answered 06/08/24
Math Tutor with Reputation to make difficult concepts understandable
Let N = # of nickels
D = # of dimes
Then:
N + D = 27 (27 coins in total)
5N + 10D = 175 (this represents the number of cents--each nickel is worth five cents, each dime ten cents).
I would use the substitution method here, because it is simple to isolate one of the variables in the 1st equation:
N = 27 - D
Now substitute that expression for N into the other equation (substitution method).
5(27 - D) + 10D = 175
135 - 5D + 10D = 175
5D = 40
D = 8
If D = 8, N = 27 - 8 = 19
19 nickels
8 dimes
-- 27 coins in total
Check:
19 nickels = 19(.05) = $0.95
8 dimes = 8(.10) = $0.80
$0.95 + $0.80 = $1.75