Will you please give me some good Short cut tricks to solve reasoning and numerical aptitude questions in bank exams??

To attempt the numerical ability and reasoning questions you should do Regular practice. It is one of the effective methods to clear QA and Reasoning in bank P.O exams.

The numerical ability test covers basic arithmetic (addition, subtraction multiplication and division), number sequences and simple mathematics (percentages, powers, fractions, etc). you should be well prepared for all these topics.

Here I am giving you some tips which will help you in cracking the examination:

Sharpen your quant skills
Make use of analytics
Master the basics
Sharpen your data interpretation skills
Learn how to use a calculator
Estimations are key
Practice 24/7

Short Cut Methods/Tricks In Percentages

When any value increases by
10%, it becomes 1.1 times of itself. (since 100+10 = 110% = 1.1)
20%, it becomes 1.2 times of itself.
36%, it becomes 1.36 times of itself.
4%, it becomes 1.04 times of itself.
Thus we can see the effects on the values due to various percentage increases.

When any value decreases by
10%, it becomes 0.9 times of itself. (Since 100-10 = 90% = 0.9)
20%, it becomes 0.8 times of itself
36%, it becomes 0.64 times of itself
4%, it becomes 0.96 times of itself.