A car travels 240 km in 6 hours it travels partly at a speed of 60 km/hr and partly at a speed of 30 km/hr then the time in hours it travels at speed of 30 km/hr is
Answers
A car travels 240 km in 6 hours it travels partly at a speed of 60 km/hr and partly at a speed of 30 km/hr then the time in hours it travels at speed of 30 km/hr is 4 hours
Given:
i) A car travels 240 km in 6 hours
ii) It travels partly at a speed of 60 km/hr and partly at a speed of 30 km/hr
To find:
Time in hours it travels at speed of 30 km/h
Solution:
Let the car travel at a speed of 30 km/h for x hours.
Distance covered by the car in those x hours = speed * time
= 30 * x
= 30x km
Remaining time = (6 - x) hours. Car travels at a speed of 60 km/hr in these (6 - x) hours.
Distance covered by the car in these (6 - x) hours = speed * time
= 60 * (6 - x)
= 60(6 - x) km
Total distance = 30x + 60(6 - x) = 240
=> 30x + 60(6 - x) = 240
=> 30x + 360 - 60x = 240
=> -30x = 240 - 360
=> -30x = -120
=> x = 4 hours
The time in hours it travels at speed of 30 km/hr is 4 hours
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