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: two consultants can type up a report in 12.5 hours and edit it in 7.5 hours . if mary needs 30 hours to type the report and jim needs 12 hours to edit it alone , how many r hours will it take if jim types the report and mary edits it immediately after he is done ? 
Options: a ) 41.4 , b ) 34.1 , c ) 13.4 , d ) 12.4 , e ) 10.8
a

Problem: circular gears p and q start rotating at the same time at constant speeds . gear p makes 10 revolutions per minute and gear q makes 40 revolutions per minute . how many seconds after the gears start rotating will gear q have made exactly 15 more revolutions than gear p ? 
Options: a ) 12 , b ) 15 , c ) 20 , d ) 24 , e ) 30
e

Problem: two spherical balls lie on the ground touching . if one of the balls has a radius of 7 cm , and the point of contact is 10 cm above the ground , what is the radius of the other ball ( in centimeters ) ? 
Options: a ) 30 / 7 , b ) 50 / 3 , c ) 70 / 4 , d ) 80 / 5 , e ) 90 / 8

c