CBSE Class 10 Mathematics
Question 18 of 29
Probability — Question Ex 15.1 Q17
Back to all questions Ex 15.1 Q17
Question (i) A lot of 20 bulbs contain 4 defective ones. One bulb is drawn at random from the lot. What is the probability that this bulb is defective?
(ii) Suppose the bulb drawn in (i) is not defective and is not replaced. Now one bulb is drawn at random from the rest. What is the probability that this bulb is not defective?
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CBSE Class 10 Probability — Complete Guide
Probability is an easy-to-score chapter worth 4-5 marks. Classical probability with coins, dice, cards, and bags.
Quick Revision: Key Concepts
- P(E) = favourable / total outcomes
- Complementary: P(E) + P(not E) = 1
- Range: 0 ≤ P(E) ≤ 1
- Cards: 52 total, 4 suits, 12 face cards, 26 red, 26 black
Most Important Questions
- Coin and dice probability problems
- Playing card probability (specific suit, face card, etc.)
- Balls in a bag problems
- Number/divisibility probability problems
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