Performance

Two masons with the same performance would have been made of plaster for six days. One of them, however, has increased its daily performance by 50%. How long would it take them now to make plaster together?

Correct answer:

t =  4 d

Step-by-step explanation:

$$\begin{gathered} a=2\cdot 6=12\text{d} \\ b=2\cdot 6=12\text{d} \\ {b}_1=b-\frac{50}{100}\cdot b=12-\frac{50}{100}\cdot 12=6\text{d} \\ t=\frac{1}{1/a+1/b_1}=\frac{1}{1/12+1/6}=4\text{d} \end{gathered}$$

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