Q. Arrange P,Q and R in order :
P=223/222*224, Q=224/223*225 R=1/224
in such questions, if you try to solve normally then its difficult to solve in 5 seconds. Whenever you see such type of questions you can see 22 is common to remove that now it reduces like
P=3/2*4 Q=4/3*5 R=1/4
P=3/8 Q=4/15 R=1/4
P=.375 Q=.26 R=.25
so P>Q>R
In this way, by mere observation, you will be able to solve questions of quantitative aptitudes.