A ship with a faulty engine sailed for only 7 hours over a period of 2 days and covered a distance of 59 km. Its average speed on the first day was \(5 \text{ km}\) per hour slower than that on the second day. But it sailed 3 hours longer on the first day than that on the second day. What was its average speed on the second day?

Explanation: ধরে নিই, দ্বিতীয় দিন এর avg. speed ছিল \(x\)। ∴ প্রথম দিন এর avg. speed ছিল \(x- 5\)। ধরে নিলাম, জাহাজ কি দ্বিতীয় দিন এ \(t\) hours ধরে চলছে, ∴ প্রথম দিন \(t+3\) hours চলছে। বলা আছে, \(t + t +3 = 7 \Rightarrow 2t = 4, t = 2, t+3 = 5\)। আমরা জানি, distance \(= \text{speed} \times \text{time}\)। সুতরাং, \(2x + 5(x - 5) = 59 \Rightarrow 2x + 5x - 25 = 59 \Rightarrow 7x=84 \Rightarrow x = 12\)।