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Skilled workshop master washes client's car in 1/5 hour, cleans client's car in 5/4 hour, and paints small defects on car 1 1/3 hour. How long did it take him to do all the necessary work tasks?

Correct answer:

t =  2 ⁴⁷⁄₆₀ = 167/60 h

Step-by-step explanation:

$$\begin{gathered} m=1\frac{1}{3}=1+\frac{1}{3}=\frac{1\cdot 3+1}{3}=\frac{3+1}{3}=\frac{4}{3}\doteq 1.3333\text{h} \\ t=\frac{1}{5}+\frac{5}{4}+m=\frac{1}{5}+\frac{5}{4}+\frac{4}{3}=\frac{12}{60}+\frac{75}{60}+\frac{80}{60}=\frac{12+75+80}{60}=\frac{167}{60}=\frac{167}{60}\text{h}=2\frac{47}{60}\text{h}=2.7833\text{h} \end{gathered}$$

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