Six identical coins are arranged in a row. The number of ways in which the number of tails is equal to number of heads is _______.
20
120
9
40
P, Q, R, S are to give lectures to an audience. The organizer can arrange the order of their presentation in ______.
4 ways
12 ways
256 ways
24 ways
The possible out comes when a coin is tossed five times.
25
52
10
5/2
The number of selections of 2 candidate for a post out of 5 equally qualified candidates.
P ( 5, 2 )
5 !
( 5 - 2 ) !
The number of ways in which 5 women, can draw water from 5 taps, no tap remaining unused is _______.
5 x 5
None of these
How many different arrangements can be made out of the letters in the expansion A2 B3 C4, when written in full ?
2! + 3! + 4!
2 ! 3!
There are four letter boxes in a post office. In how many ways can a man post 8 distinct letters.
8 x 8
84
4 8
8 p 4
In how many ways can 7 persons sit around a table.So that all shallnot have the same neighbours in any two
arrangements?
180
260
360
720
The number of ways in which 21 objects can be grouped into three groups 8,7 and 6 objects is _____
How many 10 digits number can be written by using the digits 1 and 2.
10 C1 +9 C2
2 10
10C1
10 !
