Advertisements
Advertisements
प्रश्न
If 20 points are marked on a circle, how many chords can be drawn?
उत्तर
To draw a chord we need to join two points on the circle.
There are 20 points on the circle.
∴ We can draw 20C2 chords of the circle.
= `(20!)/((20 - 2)!2!)`
= `(20!)/(18!2!)`
= `(20 xx 19xx18!)/(2xx1xx18!)`
= 190
190 chords can be drawn.
APPEARS IN
संबंधित प्रश्न
If `""^"n""P"_"r" = 1814400` and `""^"n""C"_"r"` = 45, find r.
If `""^"n""C"_("r" - 1)` = 6435, `""^"n""C"_"r"` = 5005, `""^"n""C"_("r" + 1)` = 3003, find `""^"r""C"_5`.
Find the number of diagonals of an n-shaded polygon. In particular, find the number of diagonals when: n = 12
Ten points are plotted on a plane. Find the number of straight lines obtained by joining these points if no three points are collinear.
Ten points are plotted on a plane. Find the number of straight lines obtained by joining these points if four points are collinear.
A word has 8 consonants and 3 vowels. How many distinct words can be formed if 4 consonants and 12 vowels are chosen?
In how many ways can a boy invite his 5 friends to a party so that at least three join the party?
A committee of 10 persons is to be formed from a group of 10 women and 8 men. How many possible committees will have at least 5 women? How many possible committees will have men in the majority?
Find n and r if nCr–1 : nCr : nCr+1 = 20 : 35 : 42
If 20 points are marked on a circle, how many chords can be drawn?
Find the number of diagonals of an n-sided polygon. In particular, find the number of diagonals when n = 12
Ten points are plotted on a plane. Find the number of straight lines obtained by joining these points if four points are collinear
A word has 8 consonants and 3 vowels. How many distinct words can be formed if 4 consonants and 2 vowels are chosen?
Find the value of `sum_("r" = 1)^4 ""^((21 - "r"))"C"_4`
Find the differences between the greatest values in the following:
14Cr and 12Cr
Five students are selected from 11. How many ways can these students be selected if two specified students are not selected?
Select the correct answer from the given alternatives.
The number of ways in which 5 male and 2 female members of a committee can be seated around a round table so that the two females are not seated together is
A student passes an examination if he secures a minimum in each of the 7 subjects. Find the number of ways a student can fail.
If 'n' is positive integer and three consecutive coefficient in the expansion of (1 + x)n are in the ratio 6 : 33 : 110, then n is equal to ______.
