GATE 2016 CS (CS2) – Question 15

Engineering Mathematics · Probability and Statistics · 1 mark · Numerical answer

A shop has equal numbers of two LED bulb types. The probabilities of lasting more than 100 hours are 0.7 for type 1 and 0.4 for type 2. Find the probability for a uniformly chosen bulb.

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Correct answer: 0.55 to 0.55

Explanation

Each type has probability one half. By total probability the desired value is 0.7×0.5 + 0.4×0.5 = 0.55. The equal stock sizes are what justify using equal weights.

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