A piggy bank contains the same number of nickels, dimes and quarters. If the coins total $3.20, then how many of each type of coin does the piggy bank contain?

Answer 1

Huimin,

Lets call the number of nickels q (for “question”).

how much money is in one nickel? 0.05 is the answer in dollars.

How much money in q nickels? (0.05 * q)

Similarly, how much money in q dimes? (0.10 * q)

And how much money in q quarters? (0.25 * q)

So what is the expression for total money in q nickels, q dimes, and q quarters?

Total = 0.05q + 0.10q + 0.25q

Now express this with the factor q:

Total = q (0.05+0.10 +0.25) = q(0.4)

We are told the total, so put that into the expression:

3.20 = q * 0.4

Now solve for q to find out how many nickels, dimes, and quarters were in the bank.