1. The value of 0! = ............ . 2. The number of arrangement taken 5 at a time out of n distinct element (Repitition is allowed) ............ .

Question

Fill in the blanks:    

1. The value of 0! = ............ .

2. The number of arrangement taken 5 at a time out of n distinct element (Repitition is allowed) ............ .

3. If ⁿP_r = 840, ⁿc_r = 35 then r = ........... .

4. The value of ¹⁵C₈ + ¹⁵C₉ - ¹⁵C₆ - ¹⁵C₇ = ............ .

5. The number of six-digit number, all digits of which are odd is ............ .

Answer 1

1. 1

2. n⁵

3. 4

4. 0

5. 5⁶