Question

I have $2.25 in nickels and quarters. I have three more nickels thank quarters. How many nickels and quarters do I have?

Answer 1

N: number of nickels I have

Q: number of quarters I have

Then, if I have $2.25 in total, this means that:

0.05*N + 0.25*Q = 2.25 ...(1)

I have three more nickels than quarters:

N = 3 + Q ...(2)

Using (2) on (1), and solving the equation for Q:

0.05*(3 + Q) + 0.25Q = 2.25

0.15 + 0.05Q + 0.25Q = 2.25

0.30Q = 2.10

Q = 7

Using this result in (2):

N = 3 + 7

N = 10