Aptitude tests / Mental Ability is one stream which is vital in every competitive exam. Involving tedious mental calculations and applications , this subject deals with problems which we need to reason out and analyse very closely. In this blog, I have put together few important topics and formulas from various Mental Ability chapters. Calendar In an ordinary year , the first day and the last day of the year are same In a leap year , the first and last day will be subsequent days ( Odd days -- Odd days basically means the number of days which donot form a complete week , for example 365 days forms 52 weeks and 1 day , hence this extra 1 days forms the odd day in a ordinary year) Ordinary year = 1 odd day Leap year = 2 odd days 100 years = 5 odd days 200 years = 3 odd days 300 years = 1 odd day 400 years = 0 odd days No. of leap years in 100 years = 24 leap years 200 years = 48 leap years 300 years = 72 leap years 400 years = 97 leap y...