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: in a garden , there are 10 rows and 12 columns of mango trees . the distance between the two trees is 2 metres and a distance of one metre is left from all sides of the boundary of the garden . the length of the garden is ? 
Options: a ) 12 , b ) 27 , c ) 24 , d ) 29 , e ) 11
c

Problem: a man rows his boat 75 km downstream and 45 km upstream , taking 2 1 / 2 hours each time . find the speed of the stream ? 
Options: a ) 6 , b ) 7 , c ) 5 , d ) 8 , e ) 9
a

Problem: two pipes can fill a tank in 30 minutes and 20 minutes . an outlet pipe can empty the tank in 15 minutes . if all the pipes are opened when the tank is empty , then how many minutes will it take to fill the tank ? 
Options: a ) 48 , b ) 54 , c ) 60 , d ) 66 , e ) 72

c