3/8 th of a vessel is filled with water and if 8 litres water be poured in it, 5/6 of the vessel still remain vacant. Find the capacity of the vessel.
Please solve it step by step.

Its answer is 118/5

Your answer is incorrect. If it takes 8 liters to fill the vessel from 3/8 ful to 5/6 full, then you can set up an equation like this:

8 liters = x liters times (5/6-3/8)

where x is the total volume of the vessel. Now solve for x.