Free time

Anita had 2 1/4 hours of free time in the afternoon. She spent 2/3 of her free time playing sports and watching TV for 30 minutes. How much time did she have left to read the book? Express the result as fractions of hours and numbers in minutes.

Correct answer:

t₁ =  1/4 h
t₂ =  15 min

Step-by-step explanation:

$$\begin{gathered} v=2\frac{1}{4}=2+\frac{1}{4}=\frac{2\cdot 4+1}{4}=\frac{8+1}{4}=\frac{9}{4}=2.25\text{h} \\ {t}_1=v-v\cdot \frac{2}{3}-\frac{30}{60}=\frac{9}{4}-\frac{9}{4}\cdot \frac{2}{3}-\frac{30}{60}=\frac{1}{4}\text{h}=0.25\text{h} \end{gathered}$$

$t_2=t_1\to \text{min}=t_1\cdot 60\text{min}=0.25\cdot 60\text{min}=15\text{min}=15\text{min}$

Try another example