Rohan and Sohan can do a piece of work together in 30 days.
Sohan and Mohan can do same piece of work together in 24 days.
Rohan and Mohan can do same piece of work together in 40 days.
Who will take least days to complete same work if done alone?

Respuesta :

Answer:

Sohan

Step-by-step explanation:

she was the one who made it faster to do the work!!

The reciprocal of the time it takes to do the work together is the sum of

the reciprocal of the time it takes to do the work individually.

  • Sohan will take the least number of days (40 days) to do the work

Reasons

Let R represent the number of days it will take Rohan, S, the number of

days it would take Sohan, and M, the number of days it would take Mohan

to do the work alone, we have;

[tex]\displaystyle \frac{1}{30} = \mathbf{ \frac{1}{R} + \frac{1}{S}}[/tex]...(1)

[tex]\displaystyle \frac{1}{24} = \mathbf{ \frac{1}{M} + \frac{1}{S}}[/tex]...(2)

[tex]\displaystyle \mathbf{ \frac{1}{40}} = \frac{1}{R} + \frac{1}{M}[/tex]...(3)

Subtract equation (1) from equation (2) and add the result to equation (3), we have;

[tex]\displaystyle \frac{1}{24} - \frac{1}{30} =\displaystyle \left( \frac{1}{M} + \frac{1}{S} \right) - \left(\frac{1}{R} + \frac{1}{S}\right) =\displaystyle \left( \frac{1}{M} - \frac{1}{R} \right)[/tex]

[tex]\displaystyle \frac{1}{24} - \frac{1}{30} + \frac{1}{40} =\displaystyle \left( \frac{1}{M} - \frac{1}{R} \right) + \frac{1}{R} + \frac{1}{M} = \frac{2}{M}[/tex]

[tex]\displaystyle \mathbf{\frac{1}{24} - \frac{1}{30} + \frac{1}{40}} = \frac{1}{30} = \frac{2}{M}[/tex]

M = 2 × 30 = 60

  • M = 60

[tex]\displaystyle \frac{1}{24} = \mathbf{\frac{1}{M} + \frac{1}{S}}[/tex]

[tex]\displaystyle \frac{1}{24} = \frac{1}{60} + \frac{1}{S}[/tex]

[tex]\displaystyle \frac{1}{24} - \frac{1}{60} =\frac{1}{40} = \frac{1}{S}[/tex]

[tex]\displaystyle \frac{1}{S} = \frac{1}{40}[/tex]

  • S = 40

[tex]\displaystyle \frac{1}{40} = \frac{1}{R} + \frac{1}{M}[/tex]

[tex]\displaystyle \frac{1}{40} = \mathbf{\frac{1}{R} + \frac{1}{60}}[/tex]

[tex]\displaystyle \frac{1}{40} - \frac{1}{60} = \frac{1}{120} = \frac{1}{R}[/tex]

  • R = 120

Therefore;

  • The one who takes the least number of days to do the work is Sohan, S = 40

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