Convert 7.8.9.10.11.12.13.14.15 into factorial
7!
15!/6!
15!/7!
(15-6)!
If nc4 = nc6,then the n=
8
10
2
12
The number of ways in which n different beads can be arranged to form necklace are
(n+1)!
n!
(n-1)!/2
(n+1)!/2
In how many ways can 7 persons sit around a table.So that all shall not have the same neighbours in any two arrangements?
180
260
360
720
The number of diagonals that can be drawn by joining the angular points of a polygon of 20 sides are
190
210
20
170
In how ways can 18 different books be divided equally among 3 students?
18!
18!/(6!)2
18!/(6!)3
18!/6!
If nCr denotes the number of combinations of n things taken r at a time,then the expression n(r+1+n(r-1)+2*nCr equals
n+1Cr+1
n+2Cr
n+2Cr+1
n+1Cr
Suppose the word 'PENCIL' is given to us and we have to form words with the letters of this word,in how many ways we arrange if all words begin with a particular letters.
360 ways
720 ways
24 ways
120 ways
How many numbers of 3 digits can be formed with the digits 1,2,3,4,5 when digits may be repeated?
25
125
725
5
