Question 515404
For this problem, we need to break it down into pieces and work on it. We're given the information that the money increase from $7.40 to $10.80. By using subtraction:

$10.80 - $7.40 = $3.40

We find it changes by $3.40. I says the quarter are increased by 8. Since each quarter is worth $.25, we know that $2.00 of that increase is from quarters. That leaves us with $1.40. It also says that nickels are doubled. Since each nickle is worth $.05, we use division:

$1.40 / $.05 = 28 nickels

So there are $1.40 worth, or 28, nickels in the $7.40. Now subtraction:

$7.40 - $1.40 = $6.00

So, there is $6.00 worth of quarters:

$6.00 / $.25 = 24 quarters

Which is 24 quarters, which is your answer.

Hope this helped, all the best.
-mucklef