Practicing Success
For the first part of her journey, Sunita travelled at a speed of 450 m/min and, for the rest of the journey, at a speed 1.4 times of her initial speed. If Sunita travelled a total distance of 33.3 km in 1hour, what was the distance that Sunita travelled at a lower speed? |
11.50 km 11.15 km 11.25 km 11.20 km |
11.25 km |
Speed1 = 450 meter/min = 450 × \(\frac{3}{50}\) = 27 km/h T1 + T2 = 1 hour \(\frac{D}{S1}\) + \(\frac{33.3 - D }{S2}\) = 1 \(\frac{D}{27}\) + \(\frac{33.3 - D }{27 × 1.4}\) = 1 \(\frac{33.3 - D }{27 × 1.4}\) = 1 - \(\frac{D}{27}\) 0.4D = 27 × 1.4 - 33.3 D = \(\frac{37.8 - 33.3}{0.4}\) D = \(\frac{4.5}{0.4}\) = 11.25 km |