Question

A person on a trip has a choice between private car and public tarnsport. The probability of using a private car is 0.45. While using the public transport further choices available are bus and metro, out of which the probability of commuting by a bus is 0.55. In such a situation, the probability (rounded up to two decimals) of using a car, bus and metro respectively would be

• A. 0.45, 0.30 and 0.25
• B. 0.45, 0.25 and 0.30
• C. 0.45, 0.55 and 0.00
• D. 0.45, 0.35 and 0.20

Answer 1

The correct option is A 0.45, 0.30 and 0.25

Obviously, probability of using a car = 0.45

Probability of using a bus = Probability of using public transport × prob. of commuting by a bus
= (1 - 0.45) × (0.55)
= 0.3025
$\simeq 0.30$

Probability of using a metro = (Prob. of using public transport) × (Prob. of commuting by metro)
= (1 - 0.45) (1 - 0.55)
= (0.2475)
$\simeq 0.25$