Answer:
There are 2 nickels and 6 dimes.
Step-by-step explanation:
Nickels: x
Dimes: y
Constraints:
0.05x + 0.10y = 0.70
x + y = 8 ===> -0.05 * (x + y = 8) ===> -0.05x - 0.05y = -0.4
Add the two equations to eliminate x variable:
0.05x + 0.10y = 0.70
-0.05x - 0.05y = -0.4
_________________
0.05y = 0.3 ===> y = 6
Substitution to find x:
x + y = 8
x + 6 = 8
x = 2
There are 2 nickels and 6 dimes.