Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
In a bolt factory, machines X, Y, Z manufacture bolts that are respectively $25 \%, 35 \%$ and $40 \%$ of the factory's total output. The machines $\mathrm{X}, \mathrm{Y}, \mathrm{Z}$ respectively produce $2 \%, 4 \%$ and $5 \%$ defective bolts. A bolt is drawn at random from the product and is found to be defective. What is the probability that it was manufactured by machine X?
MathematicsProbabilityNDANDA 2018 (Phase 2)
Options:
  • A $\frac{5}{39}$
  • B $\frac{11}{39}$
  • C $\frac{20}{39}$
  • D $\frac{34}{39}$
Solution:
2187 Upvotes Verified Answer
The correct answer is: $\frac{5}{39}$
Required probability
$=\frac{25 \times 2}{25 \times 2+35 \times 4+40 \times 5}=\frac{5}{39}$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.