Answer:
15 nickels and 8 dimes
Explanation:
Create a system of equations where d is the number of dimes and n is the number of nickels:
0.1d + 0.05n = 1.55
n = d + 7
Solve with substitution by plugging in d + 7 as n:
0.1d + 0.05(d + 7) = 1.55
0.1d + 0.05d + 0.35= 1.55
0.15d + 0.35 = 1.55
0.15d= 1.2
d = 8
Plug in 8 as d to find n:
n = d + 7
n = 8 + 7
n = 15
So, there are 15 nickels and 8 dimes