## How to Prepare for board Exams?

In my previous post of this series, we discussed the advantages of CBSE board exams. Now I am suggesting a few tricks about How to Prepare for board exams.
There are a lot of post on the internet that suggests you how to eat, how to sleep and how to manage your stress during board exam but in this post, I shall only discuss the academic tips about How to Prepare for board exams. I am taking class 10 Mathematics as a base subject here but you can apply more or less same tricks on almost all your subjects.

Question Paper Break-Up

## Permutations and Combinations-algebra tutors

### Permutations and Combinations(part-2)

In my previous post, we discussed the fundamental principle of counting and various methods of permutations. In this post, I shall discuss combinations in details.

Meaning of Combination- If we are given a set of objects and we want to select a few objects out of this set, then we can do it by many different ways. These ways are known as combinations.
Example- If we are given three balls marked as B, W and R and we want to select two balls then we can select like this- BW, BR, WR.

These are known as the combination of this selection.

Combination of n different objects taken r at a time when repetition is not allowed– If repetition is not allowed the number of ways of selecting r objects out of a group of n objects is called

=

In latest notation system   is also known as C(n;r) or

Properties of  – It’s a very useful and interesting Mathematical tool. It has following properties.

(i)

(ii)

(iii)      known as Pascal’s law

(iv) r.

(v)

(vi) If n is even then we should put r=n/2 for maximum value of   and if n is odd then   is greatest when r=

(vii) In the expansions of  if we put x=1 then