Jacy has a collection of 140 coins worth $19.00. She has only nickels, dimes, and quarters. The difference in the number of dimes and the number of quarters is 10. Using matrices, how many nickels are in Jacy's collection? 38 50 95 130

Let the number of dimes be x and that of nickels be (x-10). To calculate the number of dimes and nickel in $19 we shall proceed as follows;

1 dime=$0.1

1 quarter=$ 0.25

thus forming the equations:

x + (x-10) = 140 ... i

0.1x+0.25y=19 ... ii

from (i)

2x-10=140

2x=140+10

2x=150

x=150/2=75

We conclude that Jacy has 75 dimes and 65 nickels