John does $$ \frac{1}{2} $$ piece of work in 3 hours, Joe does $$ \frac{1}{4} $$ of the remaining work in 1 hour and George finishes remaining work in 5 hours. How long would it have taken the three working together to do the work ?

John can do $$\frac{1}{2}$$ work in 3 hours , So he can complete entire work in 6 hours.

Remaining work = 1- 1/2 = 1/2

Joe does 1/4 of the remaining work i.e 1/8 work in 1 hour , So he can complete entire work in 8 hours.

Now remaining work = 3/8

George finishes remaining work in 5 hour.

George do 3/8 work in 5 hours ,So he can complete entire work in 40/3 hours.

If all three work together , then ,

$$\frac{1}{6} + \frac{1}{8} + \frac{3}{40} = \frac{30}{11}$$

So , the answer would be option d)$$ 2 \frac{8}{11} hours $$