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 perimeter of a semi circle is 122 cm then the radius is ?
Options: a ) 17 , b ) 28 , c ) 24 , d ) 11 , e ) 12
[EX A]: c

[EX Q]: Problem: a and b can together finish a work in 40 days . they worked together for 10 days and then b left . after another 18 days , a finished the remaining work . in how many days a alone can finish the job ?
Options: a ) 10 , b ) 24 , c ) 60 , d ) 30 , e ) 20
[EX A]: b

[EX Q]: Problem: the current in a river is 4 mph . a boat can travel 18 mph in still water . how far up the river can the boat travel if the round trip is to take 10 hours ?
Options: a ) 69 miles , b ) 85.5 miles , c ) 96 miles , d ) 100 miles , e ) 112 miles
[EX A]:
b