Answer:
Nickels; 5 cents
Dimes; 10 cents
Given that she has 30 nickels:
30(nickels) x 5(a single nickel) = $1.50
2.40 - 1.50 = $0.90, those 90 cents leftovers should then be divided by 10 cents because one dime contains 10 cents and you want to figure out how many dimes there are:
90/10 = there are 9 dimes