A completes a work in 12 days. B completes the same work in 15 days. A started working alone and after 3 days B joined him. How many days will they now take together to complete the remaining work? - IQ786

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A completes a work in 12 days. B completes the same work in 15 days. A started working alone and after 3 days B joined him. How many days will they now take together to complete the remaining work?

A completes a work in 12 days. B completes the same work in 15 days. A started working alone and after 3 days B joined him. How many days will they now take together to complete the remaining work?

4

5

6

8

Explanation

Let us Find the Work Rate $(= \frac{W}{D a y s / T i m e})$
Now, Let us Assume $x$ be the Number of Extra Days.

$(i)$ for $A = \frac{W}{1 2}$

$(i i)$ for $B = \frac{W}{1 5}$

$\Rightarrow$ $\frac{W}{1 2} (3 + x) + \frac{W}{1 5} x = W$

$\Rightarrow$ $\frac{3 + x}{1 2} + \frac{x}{1 5} = 1$

$\Rightarrow$ $x = 5$