A jar contains n nickels and d dimes. there is a total of 185 coins in the jar. the value of the coins is $12.80. how many nickels and how many dimes are in the jar?

Respuesta :

-5n + (-5d) = -100
5n + 10d = 140
Now we add the equations. The n terms cancel.
5d = 40
Divide by 5:
d = 8

N = 12