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MCQ practice · SSC Higher Mathematics Board questions · Chapter 10: Binomial Expansion

Dhaka Board 2023 Sylhet Board 2023

If C(n, r) = n!/((n − r)! r!), which is correct?

  1. i. 0! = 0
  2. ii. C(5, 2) = 10
  3. iii. C(4, 3) = C(4, 1)

Think it through first, then pick an option.

  1. a i and ii
  2. b i and iii
  3. c ii and iii
  4. d i, ii and iii
Answer and explanation

Correct answer: c ii and iii

i false: 0! = 1 (the book's conclusion); ii true: (5×4)/(1×2) = 10; iii true: both are 4; ⁿCᵣ = ⁿCₙ₋ᵣ

Why the other options are wrong

  • a i and ii: i is false: 0! = 1 (the book's conclusion); so it cannot be included.
  • b i and iii: i is false: 0! = 1 (the book's conclusion); so it cannot be included.
  • d i, ii and iii: i is false: 0! = 1 (the book's conclusion); so it cannot be included.