NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 13: Statistics and Probability - Exercise 13.3
Question 40

Question. 40

Lot of 48 mobiles: 42 good, 3 minor defects, 3 major defects. Varnika buys only good; trader sells only if no major defect. A phone is selected at random. Probability it is (i) acceptable to Varnika (ii) acceptable to trader?

Answer:

(i) \(\dfrac{7}{8}\) ; (ii) \(\dfrac{15}{16}\)

Detailed Answer with Explanation:

Total items:

There are 48 mobiles in total.

Step 1: Find probability for Varnika.

  • Varnika buys only good phones.
  • Number of good phones = 42.
  • Total phones = 48.
  • So, probability = \(\dfrac{\text{favourable outcomes}}{\text{total outcomes}} = \dfrac{42}{48}\).
  • Simplify: \(\dfrac{42}{48} = \dfrac{7}{8}\).

Step 2: Find probability for trader.

  • The trader sells all phones that do not have a major defect.
  • Phones with major defect = 3.
  • So, acceptable phones = Total – Major defects = 48 – 3 = 45.
  • Total phones = 48.
  • So, probability = \(\dfrac{45}{48}\).
  • Simplify: \(\dfrac{45}{48} = \dfrac{15}{16}\).

Final Answer:

(i) For Varnika = \(\dfrac{7}{8}\)

(ii) For trader = \(\dfrac{15}{16}\)

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