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'.

Problem: a constructor estimates that 3 people can paint mr khans house in 4 days . if he uses 4 people instead of 3 , how long will they take to complete the job ?
Options: a ) 2 , b ) 8 , c ) 1 , d ) 3 , e ) 4
d

Problem: a man can row a boat at 10 kmph in still water and the speed of the stream is 8 kmph . what is then time taken to row a distance of 90 km down the stream ?
Options: a ) 8 hrs , b ) 5 hrs , c ) 15 hrs , d ) 15 hrs , e ) 20 hrs
b

Problem: two spherical balls lie on the ground touching . if one of the balls has a radius of 3 cm , and the point of contact is 5 cm above the ground , what is the radius of the other ball ?
Options: a ) 3 cm , b ) 9 cm , c ) 12 cm , d ) 15 cm , e ) none of the these
d