A box contains 4 red and 6 blue balls. If one ball is drawn at random, what is the probability that it is red?
- A. 0.4
- B. 0.6
- C. 0.25
- D. 0.5
Explanation
There are 4 favourable outcomes out of 10 equally likely ones, so the probability is 4 over 10, that is 0.4. The probability of blue is the complement, 0.6, and the two must add to 1. Checking that the probabilities of all outcomes sum to one is a quick verification.
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