প্রশ্ন: Faruk can do a work in 12 days and Salam can do the same work in 8 days. If Faruk , Salam and Babu work together , they can complete the work in 4 days . How many days will it take Babu to complete the work alone ?

Faruk can do a work in 12 days and Salam can do the same work in 8 days. If Faruk , Salam and Babu work together , they can complete the work in 4 days . How many days will it take Babu to complete the work alone ?

in 1 day faruk can do 1/12 unit of work

in 1 day salma can do 1/8 unit of work

let asssume,

i 1 day babu can do 1/x unit of work

in 1 day babu , faruk and salma can do = (1/12 + 1/8 + 1/x) = 5x + 24/24x unit of work

given that, in 4 days they can complete 1 unit of work together

so in 1 day the can do 1/4 unit of work

hence , 5x + 24/24x = 1/4

20x + 96 = 24x

x = 24