In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: a water tank is four - fifths full . pipe a can fill a tank in 10 minutes and pipe b can empty it in 6 minutes . if both the pipes are open , how many minutes will it take to empty or fill the tank completely ? 
Options: a ) 6 , b ) 9 , c ) 10 , d ) 12 , e ) 15
d

Problem: rahul travels from a to b a distance of 200 miles in 5 hours . he returns to a in 4 hours . find his average speed ? 
Options: a ) 52.2 mph , b ) 61.9 mph , c ) 44.4 mph , d ) 35.7 mph , e ) 65.6 mph
c

Problem: with both valves open , the pool will be filled with water in 48 minutes . the first valve alone would fill the pool in 2 hours . if the second valve emits 50 cubic meters of water more than the first every minute , then what is the capacity q of the pool ? 
Options: a ) 9000 cubic meters , b ) 10500 cubic meters , c ) 11750 cubic meters , d ) 12000 cubic meters , e ) 12500 cubic meters

d