George has a collection of old stamps. Some are worth 29 cents, the rest are worth a quarter. Their total value is $5.02. How many 29 cent stamps does George have?
Let be the number of 29 cents stamps and let be the number of 25 cents stamps. Then,
Multiplying by 100 to rid the equation of decimals yields
Solving for x yields
I know is an integer, so is also an integer. I also know is divisible by (else isn't an integer). How would I use this knowledge to find ?