A person goes to his office with the speed of
60 Km/h and he is late by 10 minutes, if he go with the speed of 50 km/h
he is still late by 18 minutes. What is his correct time to reach the office ?
a) 35 mins b) 30 mins c) 38 mins d) 34 mins e) 28 mins
a) 35 mins b) 30 mins c) 38 mins d) 34 mins e) 28 mins
Answers and Explanations are welcome in comments
Correct Answer is 30 minutes
ReplyDeleteExplanation : Firstly find the Distance which he covers with a simple formula
D = [(s1*s2)/s1-s2] *Difference of time
=[(60*50)/60-50]*8/60 (Time in hours)
=300*8/60 = 40kms
Now we know he is covering a distance of 40 kms.
If the covers this 40 kms with the speed of 60 km/h. He will take 40 minutes (T=D/s) and he is late by 10 minutes.
or
If the covers this 40 kms with the speed of 50 km/h. He will take 48 minutes (T=D/s) and he is late by 18 minutes.
That means his right time to reach the office is 30 minutes