Question

A can do a piece of work in 25 days and B can finish it in 20 days.
They work together for 5 days and then A goes away. In how many
days will B finish the remaining work? I will only give points if you are explaining them.

Answer 1

Answer:

11

Step-by-step explanation:

A's 1 day's work =

$\frac{1}{25}$

Similarly,

B's 1 day's work =

$\frac{1}{20}$

A's and B's together 1 day's work =

$\frac{1}{25 } + \frac{1}{20} = \frac{4}{100} + \frac{5}{100} = \frac{4 + 5}{100} = \frac{9}{100}$

Their 5 day's work together = 5 x 1 day's work

$1 - \frac{45}{100} = \frac{100}{100} - \frac{45}{100} = \frac{100 - 45}{100 } = \frac{55}{100}$

Now, this remaining work is done by B.

Let B takes x days to complete it.

$\frac{1}{20} \times x = \frac{55}{100 }$

$x = \frac{55}{100} \times 20$

$x = \frac{55}{5 } = 11$