Question

1.Ashok and Mohan can do a piece of work in 12 days. Mohan and Binod together do it in 15 days. If Ashok is twice as good a workman as Binod. In how much time will Mohan alone Cando the work?
(a) 15days
(b) 20days
(c) 25days
(d) 35days​

Answer 1

Step-by-step explanation:

let work completed in a day by Ashok be x

let work completed in a day by Mohan be y

let work completed in a day by Binod be z

given

$12x + 12y = 1 \: \: \: \: \: (1)\\ 15y + 15z = 1 \: \: \: \: \: \: \: \: (2) \\ x = 2z \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: (3)$

using eqn (3) in eqn (1)

$24z + 12y = 1 \: \: \: \: \: \: \: \: \: \: (4)$

solving eqn (4) and eqn (2) simultaneously we have

$z = \frac{1}{60}$