Correct Answer - Option 2 : 500 km/h

**Given:**

Initial speed of the plane = 280 km/h

Initial time taken = 5 hrs

New time taken = 2 hrs 48 min = 14/5 hrs

**Formula used****:**

Speed × time = Distance travelled

**Calculation:**

Let the new speed of the plane = y km/h

∵ the distance travelled is same.

∴ 280 km/h × 5 hr = y × (14/5) hrs

⇒ y = (280 × 5 × 5)/14

⇒ y = 500 km/h