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 and b complete a work in 4 days . a alone can do it in 6 days . if both together can do the work in how many days ? 
Options: a ) 3.75 days , b ) 3.7 days , c ) 3.6 days , d ) 2.4 days , e ) 5.75 days
d

Problem: twelve machines , each working at the same constant rate , together can complete a certain job in 6 days . how many additional machines , each working at the same constant rate , will be needed to complete the job in 3 days ? 
Options: a ) 14 , b ) 12 , c ) 15 , d ) 16 , e ) 18
b

Problem: a plot abcd is as shown in figure , where af = 30 m , ce = 40 m , ed = 50 m , ae = 120 m . find the area of the plot abcd ? 
Options: ['a ) 7207', 'b ) 7206', 'c ) 7203', 'd ) 7200', 'e ) 7201']

d