Question

Mohan and Rohan can do a piece of work in 12 days Rohan alone can finish in 30 days.In how many days can Mohan alone finish the work and the answer of this question is 20 days ​

Answer 1

The work done by Mohan alone is in 20 days  .

Step-by-step explanation:

Given as :

Mohan and Rohan can do a piece of work in 12 days

Rohan alone can finish in 30 days

Let The work done by Mohan alone in = x days

According to question

One day work of Mohan and Rohan together = $\dfrac{1}{12}$

One day work of Rohan alone = $\dfrac{1}{30}$

So, One day work of Mohan alone = $\dfrac{1}{x}$

Now,

Mohan and Rohan together 1 day work = Rohan's 1 day work + Mohan's 1 day work

i.e   $\dfrac{1}{12}$  = $\dfrac{1}{30}$  +  $\dfrac{1}{x}$

or,  $\dfrac{1}{x}$  =   $\dfrac{1}{12}$  - $\dfrac{1}{30}$

or,  $\dfrac{1}{x}$  = $\dfrac{5-2}{60}$

Or, $\dfrac{1}{x}$  =  $\dfrac{3}{60}$

∴    $\dfrac{1}{x}$ = $\dfrac{1}{20}$

i.e  x = 20

So, The work done by Mohan alone in = x = 20 days

Hence, The work done by Mohan alone is in 20 days  . Answer

Answer 2

Answer:

20days

Step-by-step explanation:

Given as :

Mohan and Rohan can do a piece of work in 12 days

Rohan alone can finish in 30 days

Let The work done by Mohan alone in = x days

According to question

One day work of Mohan and Rohan together = \dfrac{1}{12}

12

1

One day work of Rohan alone = \dfrac{1}{30}

30

1

So, One day work of Mohan alone = \dfrac{1}{x}

x

1

Now,

Mohan and Rohan together 1 day work = Rohan's 1 day work + Mohan's 1 day work

i.e \dfrac{1}{12}

12

1

= \dfrac{1}{30}

30

1

+ \dfrac{1}{x}

x

1

or, \dfrac{1}{x}

x

1

= \dfrac{1}{12}

12

1

- \dfrac{1}{30}

30

1

or, \dfrac{1}{x}

x

1

= \dfrac{5-2}{60}

60

5−2

Or, \dfrac{1}{x}

x

1

= \dfrac{3}{60}

60

3

∴ \dfrac{1}{x}

x

1

= \dfrac{1}{20}

20

1

i.e x = 20

So, The work done by Mohan alone in = x = 20 days

Hence, The work done by Mohan alone is in 20 days . Answer