In a pile of coins there are seven more quarters and nickels. If there is a total of $2.65, how many quarters are there

Let n be # of nickels

let (n + 7) be # of quarters

convert 2.65 to cents:

2.65 = 265

5n + (25n + 175) = 265

30n + 175 = 265

30n = 90

n = 90/30

n = 3

answer: 3 nickels, 10 quarters