Answer: There are 5 nickels and 10 quarters.
Step-by-step 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.