thief walks at a speed of 4 km/hr and can run at 5m/sec he walked for sometime before he saw a policeman and ran away. he covered a total distance of 2.5km 20 minutes find out how much distance had he walked and in how much time before he saw the policeman
Answers
Answer: the thief walks 1 km
and the time he walks = x/4 = 1/4 hr =15 minutes
Step-by-step explanation:Walking speed of the thief = 4km/hr
Running speed of the thief = 5m/s =(5*18)/5 = 18km/hr
He covered a distance of 2.5km
Total time taken to cover this distance = 20 minutes =(20)/(60)hr = 1/3hr
Now let us assume distance travelled by the thief waking = x
then distance travelled by the thief running = total distance - distance walked
= 2.5 - x
Now total time = time walked + time runned
1/3 = x/4 +(2.5 - x)/18 (as we know that time = distance/speed)
=> 1/3 =(9x + 5 - 2x)/36
=> 1/3 = (-7x+ 5)/36
=> 1/3 * 36 = -7x+5
=> 12 = -7x + 5
=> 12 - 5 = -7x
=> x = 7/7 = 1
Therefore, the thief walks 1 km
and the time he walks = x/4 = 1/4 hr =15 minutes
please mark as brainliest