Question

A box consists of 60 wall clocks, out of which 40 are good, 15 have minor defects and the remaining are broken. What is the probability that
(i) the box will be rejected?
(ii) the clock has minor defect?

Hint:

Always reduce your fractions to the simplest form in probability answers to ensure full marks.

Answer 1

Step 1: Total number of wall clocks

Total clocks = 60
Good clocks = 40
Clocks with minor defects = 15
Remaining (broken clocks) = 60 − (40 + 15)
= 60 − 55
= 5

Step 2: Probability that the box will be rejected

The box will be rejected if a broken clock is selected.

Number of broken clocks = 5
Total clocks = 60

Probability of rejection = 5 / 60
= 1 / 12

Step 3: Probability that the clock has minor defect

Number of clocks with minor defect = 15
Total clocks = 60

Probability of minor defect = 15 / 60
= 1 / 4

Final Answer:
(i) Probability of rejection = 1 / 12
(ii) Probability of minor defect = 1 / 4