Question
A box contains 6 red, 5 green, and 4 blue balls. Two
balls are drawn randomly. What is the probability that they are of different colors?Solution
Total number of ways to choose 2 balls: 15C2 = 105 Favorable cases: Red-Green: 6 × 5 = 30 Red-Blue: 6 × 4 = 24 Green-Blue: 5 × 4 = 20 Total favorable cases = 30 + 24 + 20 = 74 Probability = 74/105 Correct answer: d.
41 28 ? 15 67 2
3 15 35 63 99 ?
4                14                  130                     512                �...
1 1 8 4 27 9 81
...Select the number from among the given options that can replace the question mark (?) in the following series.
24, 35, 51, 73, 102, ?
4 5 12 39 160 ?
...10, 22, 46, ?, 130, 190
3  16  22  ?   98   206
542Â Â Â Â Â Â 541Â Â Â Â Â Â Â 532Â Â Â Â Â Â Â 507 Â Â Â Â Â Â Â 458Â Â Â Â Â Â Â ?
...If   314     306      x      269       394    178    1480
Then, 1/3 x + 2x - x = ?
...
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