this is because nickels are worth 5 cents and quarters are worth 25 cents and the total value is 1.60. but since we have three times as many quarters as nickels so we do 5n + 75n = 1.60. But the problem with this is the right side of the equation is in terms of dollars while the left side is in terms of cents, so we convert both sides to cents and we get 5n + 75n = 160.(we could make both sides in terms of dollars, but that wasn't one of the options) hope this helps:)
