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: working alone , pump a can empty a pool in 6 hours . working alone , pump b can empty the same pool in 9 hours . working together , how many minutes will it take pump a and pump b to empty the pool ?
Options: a ) 192 , b ) 200 , c ) 208 , d ) 216 , e ) 224
[EX A]: d

[EX Q]: Problem: john and lewis leave city a for city b simultaneously at 6 a . m in the morning driving in two cars at speeds of 40 mph and 60 mph respectively . as soon as lewis reaches city b , he returns back to city a along the same route and meets john on the way back . if the distance between the two cities is 240 miles , how far from city a did john and lewis meet ?
Options: a ) 150 miles , b ) 160 miles , c ) 140 miles , d ) 170 miles , e ) 200 miles
[EX A]: b

[EX Q]: Problem: the radius of a semi circle is 3.1 cm then its perimeter is ?
Options: a ) 15.94 , b ) 12.41 , c ) 16.1 , d ) 32.92 , e ) 32.3
[EX A]:
a