Correct Answer - Option 3 : 13.33 km/h

**Given:**

Initial speed = 4km/ h

Intial time = 5 hours

Time reduced to = 1 hours 30 minutes

**Formula used:**

Speed = Distance/ Time

m/ s = 5/ 18 km/hr

**Calculation:**

Distance covered = 4 × 5

⇒ Distance covered = 20 km

⇒ Speed needed = 20/ 1.5

⇒ Speed needed = 20 × 10/ 15

⇒ Speed needed ≈ 13.33 km/ h

**∴**** speed needed is 13.33 km/h**