A piggy bank contain $5.60 in nickel and dime. The number of nickel is 8 less than 3 time the dime. How many nickel and dime are their in the piggyback?

0.05n + 0.10d = 5.60

n = 3d - 8

0.05 (3d - 8) + 0.10d = 5.60

0.15d - 0.40 + 0.10d = 5.60

0.15d + 0.10d = 5.60 + 0.40

0.25d = 6

d = 6 / 0.25

d = 24 < = = = there are 24 dimes

n = 3d - 8

n = 3 (24) - 8

n = 72 - 8

n = 64 < = = there are 64 nickels