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'.

[EX Q]: Problem: the speed at which a man can row a boat in still water is 15 km / hr . if he rows downstream , where the speed of current is 3 km / hr , how many seconds will he take to cover 90 meters ?
Options: a ) 12 , b ) 16 , c ) 17 , d ) 18 , e ) 20
[EX A]: d

[EX Q]: Problem: some persons can do a piece of work in 8 days . two times the number of these people will do half of that work in ?
Options: a ) 2 , b ) 4 , c ) 5 , d ) 6 , e ) 8
[EX A]: a

[EX Q]: Problem: during a given week a programmer spends 1 / 4 of his time preparing flow chart , 3 / 8 of his time coding and the rest of the time in debugging the programs . if he works 48 hours during the week , how many hours did he spend debugging the program .
Options: a ) 15 hrs , b ) 16 hrs , c ) 18 hrs , d ) 19 hrs , e ) 17 hrs
[EX A]:
c