Problema Solution

Roshni has 30 coins in her backpack, all nickels, dimes, and quarters. She has a total of $4.30. If Roshni has 5 more dimes than nickels, how many quarters does she have,

Answer provided by our tutors

Let the number of nickels, dimes and quarters be x, y and z respectively

x+y+z= 30

She has 5 more dimes than nickels

=> y=x+5

 

Using x+y+z =30:

z= 30-y-x

=> z= 30- (x+5) -x

=> z= 25-2x

 

Now, sum of all coins =4.30

0.05x+ 0.10y + 0.25z= 4.30

=> 0.05x + 0.10 ( x+5 ) + 0.25 ( 25-2x )= 4.30

0.05x +0.10x + 0.5 + 6.25 -0.5x= 4.30

=> 6.25 + 0.5 -4.30 = 0.5x - 0.05x - 0.10x

=> 2.45= 0.35x

=> x= 2.45/ 0.35  = 7

=> y= 12

=> z= 11