A bag holds 3 red, 3 blue and 4 green counters. Two are taken at random without replacement. What is the probability that neither is red?
Answer and explanation
Correct answer: D. 7/15
- Step 1: Non-red counters: 7 of 10. First: 7/10; second: 6/9. Step 2. 7/10 x 6/9 = 7/15. Answer: 7/15. Why not the others: 49/100 uses replacement; 14/15 is the chance of at least one non-red counter; 21/50 keeps 10 as the second denominator.
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