Apples and Oranges

Rs 12 is more than Rs 10.
20% growth is better than 18%.
140bhp is more than 120bhp.

It is easy to compare apples to apples. Any one who went to school can understand it. Doing something better than something you have already done is of course  easy to figure out. Study harder and get more marks. Put in more hours and try to get another feature in the release.  Hire more people to get the work done faster. This is natural usage of high school math.

Science or Arts, Medical or Non-Medical, MBA or MS, Job or Business, India or US, stocks or cash. Most questions of life which are worth their salt will force you to compare apples to oranges. Some people tend to be believe they can compare anything using their monitory value.  Well ask them to choose between accelerator, brake and steering.

1  +  1 =  2

1 electron   + 1 proton    = 1 neutron
1 cannibal  + 1 cannibal = 1 cannibal

1 manager  + 2 developers = some work done
2 managers + 1 developer  = don't know
0 manager + 1000's of developers = linux kernel

Math abstracts. It makes us blind to details.  It is good to be blind to details and then it is also bad to be blind to details.  May be you are not dealing with all apples. May be you have few oranges and bananas.
Prerequisite to comparing apples to oranges is realizing you are dealing with not just apples.