A car complete a journey in 5 hours. It complete half the distance at 20 kmph and the rest at 30 kmph. The length of the journey is-
Answer: (c) 120 km.
Let be the distance = X km
Time taken = 5 hrs
According to question, X/2 x 20 + X/2 x 30 = 5 (Time = distance/speed)
(3X + 2X) = 5 x 120
5X = 5 x 120
X = 120 km.
Hence, the length of the journey = 120 km.