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: a certain bacteria colony doubles in size every day for 20 days , at which point it reaches the limit of its habitat and can no longer grow . if two bacteria colonies start growing simultaneously , how many days will it take them to reach the habitat ’ s limit ? 
Options: a ) 6.33 , b ) 7.5 , c ) 10 , d ) 15 , e ) 19
[A]: e


[Q]: Problem: calculate the speed of a boat in still water ( in km / hr ) if in one hour , the boat goes 10 km / hr downstream and 4 km / hr upstream . 
Options: a ) 7 kmph , b ) 8 kmph , c ) 9 kmph , d ) 7 kmph , e ) 6 kmph
[A]: a


[Q]: Problem: the sector of a circle has perimeter of 144 cm and central angle 180 o . find its radius ? 
Options: a ) 25 cm , b ) 32 cm , c ) 14 cm , d ) 28 cm , e ) 21 cm
[A]:
d