A can do a piece of work in 10 data and B in 12 data. Find how much time they will take to complete the work, if B leaves 2 days before the scheduled completion of the work.

6.3 days
let, the work in unit = lcm(10,12)=60
A = 60/10=6 unit/day , B = 60/12 =5unit/day
now as B left 2days earlier so , subtract 2days of work of B i.e. 2*5 =10 from 60
60-10 =50
this amount of work would be done by A and B together i.e. 50/5+6 =50/11 and remaining 10 units is done by A alone = 10/6

sum of both =50/11 +10/6 =6.33 approx

70/11 days ..?

days instead of data*

10 and 12 LCM is 60 and if b leaves 2 days before so add b,s 2 days work so total days approx is 70/11= 6.36 days.

6 4/11 days

10 2/11 days

approx of 4.5 days