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Mathematics — Standard (041) — CBSE Class 10 board question

Q1. [1] § Chapter Opening and Epigraph
If the probability of a player winning a game is 0.79, then the probability of his losing the same game is :
  1. (a) 1.79
  2. (b) 0.31
  3. (c) 0.21%
  4. (d) 0.21
Previously asked in CBSE board exam
2024 30/1/1 Q2
Generated by claude-sonnet-4-6 · 2026-06-15 10:31 · grounding rag
Model Answer

(d) 0.21

P(losing) = 1 − P(winning) = 1 − 0.79 = 0.21

Source: Chapter 14, Section 14.1 (Complementary events: $P(\bar{E}) = 1 - P(E)$)

Explanation

Using the complementary event rule: P(E) + P(not E) = 1. Since P(winning) = 0.79, P(losing) = 1 − 0.79 = 0.21. Options (a) and (b) are incorrect calculations; (c) is wrong as 0.21% ≠ 0.21.

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