Answer:
50 nickels, 20 quarters.
Step-by-step explanation:
System of equations (q = # of quarters, n = # of nickels):
q + n = 70, 0.25q + 0.05n = 7.50
the first equation can be changed to q = 70 - n, so we are able to substitute q with 70 - n.
So, it will look like 0.25*70 - 0.25n + 0.05n = 7.50. This can be simplified to 0.2n = 10, which means that n = 50.
Knowing that we can solve q + 50 = 70, which means that q = 20.
