Question

A can complete a project in 20 days and B can complete the same project in 30 day If A and B start working on the project together and A quits 10 days before t project is completed, in how many days will the project be completed?​

Answer 1

Answer:

8/20 + 8/30 = 24/60 + 16/60 = 40/60 = 2/3rds of the project complete, leaving 1/3rd undone. And thus B takes 10 days to complete that, since he can do 1/30th per day. So yes, the answer is 18 days.

Answer 2

The answer to this question is 18 days.

Given,

A can complete the project in 20 days. B can complete the project in 30 days. A quits 10 days before the project is completed.

To Find,

In how many days will the project be completed?​

Solution,

This question can be solved by following this simple process.

The rate of A's work =  $\frac{1}{20}$

The rate of B's work =  $\frac{1}{30}$

Let the number of days to complete to project be 't' days.

According to the question, B works for 't' days while A works for 't-10' days.

∴

$\frac{1}{20} \times(t -10)+\frac{1}{30} \times t=1\\\\ \frac{1}{20} - \frac{1}{2} + \frac{t}{30}= 1\\\\ \frac{3t-30+2t}{60}=1\\\\ 5t-30=60\\5t=60+30\\\\t=18$

So, the project will be completed in 18 days.

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