A-can-do-a-work-in-10-days-and-B-can-do-the-same-work-in-15-days-How-many-days-will-they-take-if-both-work-together-

Question Number 9167 by nazar last updated on 21/Nov/16

A can do a work in 10 days and B can

do the same work in 15 days . How

many days will they take if both work

together ?

Commented by tawakalitu last updated on 22/Nov/16

Let the time it take both of them be = x

∴ x (\frac{1}{10} + \frac{1}{15}) = 1

∴ x (\frac{15 + 10}{150}) = 1

∴ x (\frac{25}{150}) = 1

∴ x (\frac{1}{6}) = 1

∴ \frac{x}{6} = 1

Cross multiply

∴ x = 6

Hence it will take both of them 6 days to

finish the work if they both work together .

DONE!

Commented by mrW last updated on 22/Nov/16

The solution can be generalized

as following :

Commented by mrW last updated on 22/Nov/16

Commented by sandy_suhendra last updated on 22/Nov/16

it can be solved by this way :

in 1 day A can do = \frac{1}{10} part of work

in 1 day B can do = \frac{1}{15} part of work

in 1 day A and B can do = \frac{1}{10} + \frac{1}{15} = \frac{1}{6} part of work

so A and B can do the work in 6 days