An urn contains 7 white, 5 black and 3 red balls. Two balls are drawn at random. Find the probability that i. both the balls red ii. one ball is red and the other is black iii. one ball is white.

Explanation

To solve the problem, we will calculate the probabilities for each of the three parts step by step.

### Given:
- Number of white balls = 7
- Number of black balls = 5
- Number of red balls = 3
- Total number of balls = 7 + 5 + 3 = 15

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