Question 50
Linear and Simultaneous EquationsA man drove for 4 hours at a certain speed, he then doubled his speed and drove for another 3 hours. Altogether he covered 600 kilometres. At what speed did he drive for the last 3 hours?
- A.120km/hr
- B.60km/hr
- C.600/7km/hr
- D.50km/hr
- E.100km/hr.
Show the answer and explanation
Answer: A (120km/hr)
Explanation
With first speed v: 4v + 3(2v) = 10v = 600, so v = 60km/hr. The last 3 hours were at 2v = 120km/hr.