Question

Raghu can do a job in 12 days alone and Sam can do the same job in 15 days alone. A third person Aru whose efficiency is two-third of efficiency of both Ram and Shyam together, can do the same job in how many days alone?
A) 10
B) 12
C) 13
D) 15

Answer 1

Hii dear here is your answer


option a is the correct answer
Hope it's help u

Answer 2

$\bold{QUESTION-}$Raghu can do a job in 12 days alone and Sam can do the same job in 15 days alone. A third person Aru whose efficiency is two-third of efficiency of both Ram and Shyam together, can do the same job in how many days alone?
A) 10
B) 12
C) 13
D) 15

Answer:   A) 10 

$\underline{\underline{\Huge\mathfrak{Solution-}}}$

One day work of Raghu and Sam together =

$\frac{1}{12} + \frac{1}{15} = \frac{9}{60} = \frac{3}{20}$

Aru $\bold{efficiency}$
= 2/3 of (Raghu + Sam)

Number of days required for Aru to do thw work alone =

$\frac{3}{2} \times \frac{20}{3} = 10days$