Together 3

If Sally can paint a house in 4 hours, and John can paint the same house in 6 hours, how long will it take for both of them to paint the house together?

Correct answer:

t =  2.4 h

Step-by-step explanation:

$$\begin{gathered} h_1=1\mathrm{/}4={\displaystyle \frac{1}{4}}=0.25 \\ {h}_2=1\mathrm{/}6={\displaystyle \frac{1}{6}}\doteq 0.1667 \\ t={\displaystyle \frac{1}{h_1+h_2}}={\displaystyle \frac{1}{0.25+0.1667}}={\displaystyle \frac{12}{5}}\text{ h}=2.4\text{ h} \end{gathered}$$

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