A collection of dimes and quarters worth $9.25. There are 46 coins in all. Find how many of each there are. How many dimes are there?

If all were quarters, the value would be 46*$0.25 = $11.50. The actual value is $2.25 less than that. Replacing a quarter with a dime reduces the value by $0.15, so there must be $2.25/$0.15 = 15 dimes

There are 15 dimes.