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 + d = 17

5N + 10d = 115 <--- amount in pennies

N d k

1 1 17

5 10 115

-5 * row1 + row2

----------------

1 1 17

0 5 30

5d = 30

d = 6

then b=11

11 nickles and 6 dimes

check:

0.55 + 0.6 = 1.15

11 nickles and 6 dimes