Steven has a collection of nickles and dimes.In all he has 17 coins The total value of the collection is 1.15 $ How many nickles and dimes does he have? Solve this qustion using matrices.

Answer 1

N = number of nickels D = number of dimes

N + D = 17

0.05N + 0.10D = 1.15

multiply the first equation by 0.05: 0.05N + 0.05D = 17(0.05)=0.85

0.05N + 0.10D = 1.15

0.05N + 0.05D = 0.85 subtract the bottom equation from the top equation

0.05D = 0.30

D = 0.30/0.05 = 6

N + D = 17

N + 6 = 17

N = 17 - 6 = 11

Check

0.05N + 0.10D = 1.15

0.05(11) + 0.10(6) = 1.15

0.55 + 0.60 = 1.15 Yes

N = 11 = number of nickels

D = 6 = number of dimes