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: an seller earns an income of re 1 on the first day of his business . on every subsequent day , he earns an income which is just thrice of that made on the previous day . on the 20 th day of business , he earns an income of : 
Options: a ) 29 , b ) 57 , c ) 35 , d ) 20 , e ) 30
[EX A]: b

[EX Q]: Problem: what is the greatest possible length which can be used to measure exactly the lengths 10 m 50 cm , 14 m 55 cm and 50 cm ? 
Options: a ) 20 cm , b ) 24 cm , c ) 30 cm , d ) 10 cm , e ) 5 cm
[EX A]: e

[EX Q]: Problem: in what time will a train 100 m long cross an electric pole , it its speed be 144 km / hr ? 
Options: a ) 2.5 sec , b ) 2.8 sec , c ) 8.5 sec , d ) 2.2 sec , e ) 4.5 sec
[EX A]:
a