Question

You have 15 coins in your pocket that are quarters or nickels. They total $2.75. How many of each coin do you have?

Answer 1

Answer: There are 5 nickels and 10 quarters.

Explanation:

Let x = Nickels , y= Quarters.

Then x+y = 15

⇒ y=15-x (i)

1 nickel = 5 cents , 1 quarter = 25 cents

$2.75 = 275 cents [ 1 dollar = 100 cents ]

Then, 5x+25y= 275 (ii)

Substitute value of y from (i)

5x+25 (15-x)=275

⇒ 5x + 375 - 25x =275

⇒ -20x= 275-375

⇒ -20x= -100

⇒ x = 5 [divide both sides by -20]

Put this in (i) , we get y= 15-5=10

Hence, there are 5 nickels and 10 quarters.