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GATE 2026 PI – Question 31

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

A box contains five coated and ten otherwise identical uncoated cutting inserts, randomly mixed. An operator takes four simultaneously for a four-tooth face mill without distinguishing them. Find the probability all four are uncoated (two decimals).

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Correct answer: 0.14 to 0.16

Explanation

Sampling is without replacement. Favorable subsets number $\binom{10}4$, while all possible subsets number $\binom{15}4$. Thus $P=210/1365\approx0.153846$, giving **0.15**.

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