Question

Fitst person can take work 40 days the samwe woek anther person take 30 days and third person take 24 days they do togather how many days wull take

Answer 1

first person take 40 day to do a work

so first person 1 day work = 1/40

Second person take 30 days

so second person 1 day work = 1/30

third person take 24days only so

third person one day work = 1/24

all three person together 1 day work =

$\frac{1}{40} + \frac{1}{30} + \frac{1}{24} \\ = ( \frac{1}{120} ) \times (3 + 4 + 5) \\ = ( \frac{1}{120} ) \times 12 \\ = \frac{1}{10}$

1/10 work is done in 1 day

1 work will be done

$\frac{1}{ \frac{1}{10} } = 10$

10 days