I travel the first part of my journey at 40 kmph and the second part at 60 kmph and cover the total distance of 240 km to my destination in 5 hours. How long did the first part of my journey last?  Choose the correct answer:
A) 4 hours
B) 2 hours
C) 3 hours
D) 2 hours 24 minutes
E) None
Explanatory Answer   The total time of journey = 5 hours.   Let 'x' hours be the time that I traveled at 40 kmph   Therefore, 5 - x hours would be time that I traveled at 60 kmph.   Hence, I would have covered x*40 + (5 - x)60 kms in the 5 hours = 240 kms.   Solving, for x in the equation 40x + (5 - x)*60 = 240, we get   40x + 300 - 60x = 240   =&gt; 20x = 60 or x = 3 hours.   Answer 3 hours
<result>C</result>
I travel the first part of my journey at 40 kmph and the second part at 60 kmph and cover the total distance of 240 km to my destination in 5 hours. How long did the first part of my journey last?