Answer:
12 nickels
21 dimes
16 quarters
Step-by-step explanation:
9 extra dimes : 9 x 10 = 90
4 extra quarters : 4 x 25 = 100
total of the extras : 100 + 90 = 190
remaining amount: 670 - 190 = 480
remaining amount are made up of equal number of nickel, dimes and quarters, thus
5 + 10 + 25 = 40 ( 1 set of each type)
480 / 40 = 12 sets
therefore there are
12 nickels
12 + 9 = 21 dimes
12 + 4 = 16 quarters
