Question

Ram can complete the work in 10 hours, Ajit in 12 hours and Suresh in 15 hours. All of them began the work together, but Ram had to leave the work after 2 hours of the start and Ajit left 3 hours before the completion of the work. How long did the work last?

Answer 1

ram worked for 2 hours and Ajit worked for 12-3 =9 hours

Answer 2

ram =  10 hrs

ajit   =12hr

suresh  =15hrs

∴ total  = 15+12+10  = 37 hrs

but  ,, R  =  10 +  2 = 12 hrs  

A  =  12+ 3 = 15hrs

S = 15 hrs

∴  total time  = 12+ 15 +15 =42 hrs