A car can cover 144 km. in 1.8 hour.  In what time (in hours) will it covers double the distance when its speed is increased by 50%?

2.4 hours

S = \(\frac{144}{1.8 hour}\)                [1.8 hour = 1 + \(\frac{4}{5}\) = \(\frac{9}{5}\) hour]

S = \(\frac{144 × 5}{9}\) = 80 km/h

Increased speed by 50% = 80 + 40 = 120 km/hr

New distance = 144 × 2 = 288 km

Required Time = \(\frac{288}{120}\) = 2.4 hours