Permutations, Combinations And Binomial Theorem

Question 1

ⁿpᵣ

Answer 1

ⁿpᵣ= n!/(n-r)!

Question 2

ⁿCᵣ

Answer 2

ⁿCᵣ = n!/(n-r)!r!

Question 3

ⁿCᵣ₋₁ + ⁿCᵣ =

Answer 3

ⁿCᵣ₋₁ + ⁿCᵣ = ⁿ⁺¹Cᵣ

Question 4

Product of n consecutive integers is divisible by….

Answer 4

n!

Question 5

When things are identical, permutations become…

Answer 5

Combination

Question 6

The expansion (a+b)ⁿ has how many terms

Answer 6

(n + 1) terms

Question 7

ⁿC₁ + ⁿC₂ + ⁿC₃ +…..ⁿCₙ = ?

Answer 7

ⁿC₁ + ⁿC₂ + ⁿC₃ +…..ⁿCₙ = 2ⁿ

Question 8

What is absolute term?

Answer 8

Term independent of y, ie power of y=0

Question 9

Total no: of terms in the expansion of
(a+b)ⁿ + (a-b)ⁿ

Answer 9

if n is even:
No: of terms = (n/2) + 1

If n is odd:
No: of terms = (n+1)/2

Question 10

For circular permutation

Answer 10

Pn = (n-1)!