Question

A, b and c can do a work in 5 days, 10 days and 15 days respectively. they started together to do the work but after 2 days a and b left. c did the remaining work (in days)

Answer 1

(a+b+c)2 +(c) x=1
(1/5+1/10+1/15)2 +(1/15)x=1
(6+3+2/30)2 +x/15=1
11×2/30 +x/15=1
22/30+x/15=1
x/15=1-22/30
x/15=8/30
x=8×15/30
x=8/2
x=4days
c can do in 4 days

Answer 2

HELLO FRIEND HERE IS UR ANSWER

A does 1/12th of the work in a day.

B does 1/15th of the work in a day.

C does 1/20th of the work in a day.

So in two days that the three work together and they completed

(2/12) +(2/15) + (2/20) = (10/60) + (8/60) + (6/60) or (24/60) or 2/5th of the work. So what remains to be done is 3/5th of the work.

A and B together do (1/12) +(1/15) = (5/60) + (4/60) = 9/60

or 3/20th of the work in a day.

So the two working together will take (3/5)/(3/20) = (3*20/(5*3) = 4 days.

HOPE HELPS ✌️✌️✌️