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'.

[Q]: Problem: pipe a fills a tank of capacity 850 liters at the rate of 40 liters a minute . another pipe b fills the same tank at the rate of 30 liters a minute . a pipe at the bottom of the tank drains the tank at the rate of 20 liters a minute . if pipe a is kept open for a minute and then closed and pipe b is open for a minute and then closed and then pipe c is open for a minute and then closed and the cycle is repeated , when will the tank be full ? 
Options: a ) 42 minutes , b ) 51 minutes , c ) 39 minutes , d ) 40 minutes 20 seconds , e ) none of these
[A]: b


[Q]: Problem: the speed at which a man can row a boat in still water is 16 kmph . if he rows downstream , where the speed of current is 4 kmph , what time will he take to cover 100 metres ? 
Options: a ) 23 , b ) 27 , c ) 28 , d ) 12 , e ) 18
[A]: e


[Q]: Problem: rajani has to read a book of 445 pages . she has already read the first 157 pages of the book and if she reads 24 pages of the book everyday then how long will she take now to complete the book ? 
Options: a ) 25 days , b ) 20 days , c ) 46 days , d ) 21 days , e ) none of these
[A]:
e