Question:

The number of diagonals of a polygon of $30$ sides is

Updated On: Jul 7, 2022
  • $225$
  • $350$
  • $405$
  • $210$
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is C

Solution and Explanation

Required number $= \,^{30}C_{2} -30$ $ = 405$.
Was this answer helpful?
0
0

Top Questions on Combinations

View More Questions

Notes on Combinations

Concepts Used:

Combinations

The method of forming subsets by selecting data from a larger set in a way that the selection order does not matter is called the combination.

  • It means the combination of about ‘n’ things taken ‘k’ at a time without any repetition.
  • The combination is used for a group of data where the order of data does not matter.
  • For example, Imagine you go to a restaurant and order some soup.
  • Five toppings can complement the soup, namely:
    • croutons,
    • orange zest,
    • grated cheese,
    • chopped herbs,
    • fried noodles.

But you are only allowed to pick three.

  • There can be several ways in which you can enhance your soup with savory.
  • The selection of three toppings (subset) from the five toppings (larger set) is called a combination.

Use of Combinations:

It is used for a group of data (where the order of data doesn’t matter).