Problema Solution

Robert has 10 coins consisting of nickels and dimes. If the total value of his coins is 70 cents, how many coins of each type does he have?

Answer provided by our tutors

. x = nickels

....x + 9 = dimes

....(x + 9) + 21 = quarters

....0.05x + 0.10(x + 9) + 0.25(x + 30) = 10.00

....5x + 10(x + 9) + 25(x + 30) = 1000

....5x + 10x + 90 + 25x + 750 = 1000

....40x + 840 = 1000

....40x = 160

....x = 6 nickels

....x + 9 = 15 dimes

....x + 30 = 36 quarters