A car travels from city A to city B at an average speed of 60 km/ hr and reaches city B on time. If the car reduces its speed to 50 km/hr, it takes 16 minutes more to reach city B. What is the distance between city A and city B ? (In kilometre)

Let time taken by the car to reach city B by travelling at 60 km/hr = $$t$$ hrs

=> Time taken to reach city B by travelling at 50 km/hr = $$(t + \frac{16}{60})$$ hrs

$$\because spped \propto \frac{1}{time}$$

=> $$\frac{s_1}{s_2} = \frac{t_2}{t_1}$$

=> $$\frac{60}{50} = \frac{t + \frac{16}{60}}{t}$$

=> $$6t = 5t + \frac{16}{12}$$

=> $$6t - 5t = t = \frac{4}{3}$$ hrs

$$\therefore$$ Distance between city A & B = speed $$\times$$ time

= $$60 \times \frac{4}{3} = 80$$ km