Rachna has nickels, dimes, and quarters in her piggy bank. She has $4.65 altogether.

She has three more quarters than dimes and twice as many nickels as quarters. How many quarters does Rachna have?

A8
B11
C22
D41

Verified Answer :


we can translate the given statements into algebraic expressions. In this case, 

0.05x + 0.10y + 0.25z = 4.65z = 3 + yx = 2 z 
solving these linear equations simultaneously, x = 22y = 8z= 11hence the answer is B. 11

For this case we have the following variables:

x: number of nickels

y: number of dimes

z: number of quarters

We now write the system of equations that models the problem:

\(0.05x + 0.1y + 0.25z = 4.65  z = y + 3  x = 2z\)

Rewriting the equations as a function of z we have:

\(0.05 (2z) + 0.1 (z-3) + 0.25z = 4.65\)

From here, we clear the value of z:

\(0.1z + 0.1z - 0.3 + 0.25z = 4.65  0.1z + 0.1z + 0.25z = 4.65 + 0.3  0.1z + 0.1z + 0.25z = 4.65 + 0.3  0.45z = 4.95\)

\(z = \frac{4.95}{0.45}  z = 11\)

Answer:

The number of quarters that Rachna has is:

B. 11