Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Saurabh 1
Please find solution below.... If you want then I will share the prove , like how that formula came in seepage velocity involving porosity. But you can go through book also(Hydrogeology by Todd).