Question

Margaret's bottle of shampoo is seven eights phone. She uses 1/3 of the shampoo in the bottle to wash the dog. Estimate what fraction of shampoo is left. Use whole numbers in benchmark fractions to explain.

Answer 1

Fraction of shampoo left =  $\frac{13}{24}$

Solution:

Given fraction of full shampoo $=\frac{7}{8}$.

Fraction of shampoo Margaret used $=\frac{1}{3}$

Fraction of shampoo left = Full shampoo – fraction of shampoo used

                                           $=\frac{7}{8}-\frac{1}{3}$

To make the denominators same do cross multiplication.

                                           $\begin{aligned}&=\frac{7 \times 3}{8 \times 3}-\frac{1 \times 8}{3 \times 8}\\&=\frac{21}{24}-\frac{8}{24}\\&=\frac{21-8}{24}\\&=\frac{13}{24}\end{aligned}$

Hence $\frac{13}{24}$ of the shampoo bottle is left.