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: two pipes a and b can separately fill a cistern in 24 minutes and 48 minutes respectively . there is a third pipe in the bottom of the cistern to empty it . if all the three pipes are simultaneously opened , then the cistern is full in 12 minutes . in how much time , the third pipe alone can empty the cistern ? 
Options: a ) 90 min , b ) 48 min , c ) 54 min , d ) 120 min , e ) 130 min
b

Problem: find the area of trapezium whose parallel sides are 28 cm and 18 cm long , and the distance between them is 15 cm . 
Options: a ) 227 , b ) 299 , c ) 345 , d ) 161 , e ) 212
c

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