We are asked for the diff of atleast \($3000\).
From the graph, it is clear that all the public school expense is above \($1000\) hence for the private it should be atleast \($4000\) - to get \($3000\) difference. So you can easily remove the first \(3\) bars from consideration.
For the next \(3\) bars, the public expense is nearly \($2000\) but for private it is less than \($5000\) so difference of \($3000\) can't be achieved.
Last \(4\) did just that hence the answer.
Hope it is clear now.
Observation is the key here. One can definitely do it in 60-70 seconds.
kumarneupane4344 wrote:
sud298 wrote:
How to do this in less than a minute?
I am thinking the same, Should I need to add all those values to know the quantities are bigger or not. What is your suggestion
rx10 sir?
_________________