What is the speed of a train if it overtakes two persons who are walking in the same direction at the rate of a m/s and (a + 1) m/s and passes them completely in b seconds and (b + 1) seconds respectively?

• ক (a + b + 1) m/s ✅ সঠিক উত্তর
• খ (2a + 1) m/s
• গ 2a+122a+12 m/s
• ঘ (a + b) m/s