13 coins
nickels and quarters
total value = $2.05
nickels = n
quarters = q
What is the question? calculathe the number of nickels and quarters?
Equations
n + q = 13
0.05n + 0.25q = 2.05
Solve by substitution
n = 13 - q
0.05(13 - q) + 0.25q = 2.05
0.65 - 0.05q + 0.25q = 2.05
0.20q = 2.05 - 0.65
0.20q = 1.4
q = 1.4/0.20
q = 7
n + 7 = 13
n = 13 - 7
n = 6
