Project ForgeGeneral Aptitude
Quantitative Aptitude
GATE 2021
Medium
A box contains 15 blue balls and 45 black balls. If 2 balls are selected randomly, without replacement, the probability of an outcome in which the first selected is a blue ball and the second selected is a black ball, is _____
- A3/16
- 45/236
- C1/4
- D3/4
Explanation
Total balls = 60. P(first blue) = 15/60 = 1/4. Given the first was blue (14 blue, 45 black, 59 total left), P(second black) = 45/59. Combined probability = (1/4) x (45/59) = 45/236.
Source: GATE ME 2021 Session 2 (ME-2) (2021)
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