A man travels 50 km at a speed 25 km/hr and next 40 km at 20 km/hr and there after travel 90 km at 15 km/hr. His average speed is:

• ক 18 km/hr ✅ সঠিক উত্তর
• খ 13 km/hr
• গ 9 km/hr
• ঘ 36 km/hr