Factorial

Q. The value of 1+ 1.1! + 2.2! + 3.3! + .......... + n.n! is

1. (n+1)!+1
2. (n+1)!–1
3. (n+1) !
4. (n–1) !

Q.

Out of the numbers from 0 to 10, what fraction of them are: [4 MARKS]

1) Odd numbers
2) Prime numbers
3) Even numbers

Q. Three persons A, B and C are to speak at a function along with 5 other persons. If the persons speak in random order, the probability that A speaks before B and B speaks before C is:

1. $\frac{3}{5}$
2. $\frac{3}{8}$
3. $\frac{1}{6}$
4. $\frac{4}{15}$

Q.

The number of ways in which ten candidates $A_1,A_2,A_3......A_{10}$ can be ranked if $A_1$ and $A_2$ are next to each other is

1. 2!.11!
2. 2!.8!
3. 2!.9!
4. 2!.10!

Q.

The value of $2^n\left\{\mathrm{1.3.5.....}\right(2n-3\left)\right(2n-1\left)\right\}$ is

1. 

2. 

3. 

4. 

Q.

The number of numbers that can be formed by the digits 1, 2, 3, 4, 3, 2, 1 with the odd digits at odd places is

1. 430
   

2. 36
   

3. 18
   

4. None of these

Q.

Add the following rational numbers:

(i) (3/4) and (-3/5)

(ii) -3 and (3/5)

(2 marks)

Q.

The number of ways in which ten candidates $A_1,A_2,A_3......A_{10}$ can be ranked if $A_1$ and $A_2$ are next to each other is

1. 2!.10!
2. 2!.9!
3. 2!.11!
4. 2!.8!

Q.

The sum of the digits in the unit place of all numbers formed with the help of 3, 4, 5, 6 taken all at a time is

1. 18

2. 108

3. 144

4. 432