Correct Answer - Option 3 : 90 km
Given:
The distance covered by foot = (7/12) of the total journey
The distance covered by bus = (3/5) of the remaining journey
The distance covered by car = 15 km
Calculation:
Let the distance of the entire journey be D km.
The distance covered by the person by foot = (7/12) × D
⇒ 7D/12
The remaining distance to complete the journey = D - (7D/12)
⇒ 5D/12
The distance covered by the person by bus = (3/5) × (5D/12)
⇒ (3D/12)
Completed journey = (7D/12) + (3D/12)
⇒ 10D/12
The remaining journey = D - (10D/12)
⇒ 2D/12
According to the question,
2D/12 = 15
⇒ D/6 = 15
⇒ D = 15 × 6
⇒ D = 90 km
∴ The length of the entire journey is 90 kilometers.