Answer: 1:1.
- A 1:1
- B 50:48
- C 25:1
- D 1:25
Correct answer: A. 1:1
Explanation: 50C2 = 50C48 (by symmetry nCr = nC(n-r)). Ratio = 1:1.
Row n of Pascal's triangle gives the coefficients nC0, nC1, ..., nCn for the expansion of (a+b)ⁿ; each number is the sum of the two numbers diagonally above it, a direct visual proof of the identity nCr = (n-1)C(r-1) + (n-1)Cr.
Concept context
Expansion of (a+b) n , general term, middle term, binomial coefficients, and greatest term