How do they set up the tough IIT-JEE paper?
Take the Physics : Projectile Motion :
Now say they state a problem :
A ball is dropped from a building, and a boy throws another similar ball , horizontally from the same height at the same instant; Which Ball will touch the ground first?
Given this problem, one approach would be to use the formulas and calculate and find the answer;
but another approach would be to identify the key concept of the above problem that :
In a projectile motion, the vertical component of the Velocity of a body is independent of its Horizontal component!
By which, both the balls will touch the ground at the same time.
Not only in Science, but in any problem, rather than taking the formulaic approach:
get to the root cause and the key concept that is driving this problem!
and solve it!