Question

A and B can do a work individually in 11 and 33 days respectively. In how many days can they complete the work, working alternatively?

Answer 1

Time taken for A to finish the work= 11 days.
Time taken for B to finish the work= 33 days
Suppose time taken by each of them to finish the work be x days
Therefore,
Work done by A in 1 day = 1/11 th part of work
Work done by B in 1 day= 1/33 th part of work
Work done by A in x days = x/11 th part of work
Work done by B in x days= x/33 th part of work
Therefore,
x/11 + x/33 = 1
or, 4x/33 = 1
or, x= 33÷4
There time taken to finish the work
=33÷4 × 2 days
=16.5 days.
Hope , it helps.

Answer 2

Given:

A can do a work in 21 days.

B can do a work in 35 days.

To find:  

In how many days can they complete the work if they work alternatively.

Solution:

To find the total work done,

Find the LCM of the numbers 21 and 35,

Hence, the total work done = 105.

For A,

The work done = 21 / 105

A = 1 / 5 in a day.

For B,

The work done = 35 / 105

B = 1 / 3 in a day.

B can do 3 units /day.

Suppose A starts the work.

Day 1 = A

Day 2 = B  

Day 3 = A  

And so on,

1/5 + 1/3 + 1/5 + 1/3 ... = 105

Therefore,

It takes 26.2 days to complete the work if they work alternatively.

Hence, 26.2 days is the answer.

Read more on Brainly.in - https://brainly.in/question/6527356