Answer:
There are 16 nickels, 7 dimes, and 9 quarters.
Explanation:
Aight, so lets set dimes as "x". Since there are 2 more quarters than dimes, quarters is "x+2". And since nickels is equal to dimes plus quarters, nickels takes the role of "(x+2)+x". We can simplify this by adding x and x together, so nickels is "2x+2" In this example, I'm converting these variables to cents, since it's easier than converting to dollars. Since a dime is 10 cents, 10 times x is"10x". Quarters are worth 25, so first we do x times 25 (25x) and then 2 times 25 (50). Then nickels. 2x+2 times 5 is 10x + 10. Alright, so now we have our cent values. $3.75 is 375 cents, so now we can make an equation:
10x + 25x + 50 + 10x + 10 = 375 cents.
I'm guessing you already know how to solve an equation, first combine like terms, then figure out how many times the variable goes into the numerical value. You should end up with 7, which is dimes. If we go back to our problem, we see that there are 2 more quarters, so 7+2= 9 quarters. As for nickels (9+7) there are 16 nickels.
There's probably a more efficient way to do this, but since I'm so... uh... inefficient, this is the best explanation I can do :p