Calculate 72594

Karel, Peter, and Milan helped pick apples. It took Karl 30 minutes, Peter 45 minutes, and Milan 36 minutes to turn over one full box of apples. Calculate how long it would take them to acquire 3 full crates together.


Mark one answer:
a. 32 minutes
b. 36 minutes
c. 48 minutes
d. 54 minutes

Correct answer:

t =  36 min

Step-by-step explanation:

$$\begin{gathered} k=30\text{min} \\ p=45\text{min} \\ m=36\text{min} \\ s=1/k++1/p+1/m=1/30++1/45+1/36=\frac{1}{12}\doteq 0.08331\text{/min} \\ t\cdot s=3 \\ t\cdot 0.083333333333333=3 \\ 0.083333t=3 \\ t=\frac{3}{0.08333333}=36 \\ t=36=36\text{min} \end{gathered}$$

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