Counting Gallons Puzzle

#157

One of my friend was going from my hometown, Kaithal to Karnal, with a full tank of gasoline i.e. 23 gallons. 
But unfortunately, at that exact moment his gasoline tank sprang a leak, due to which he started losing 1 gallon of fuel each hour. 
When going to Karnal which is 60 kms away, he could only manage a speed of 12 kmph. 
But on the way back to Kaithal, he managed a speed of 16 kmph.
(He was travelling at 8 kms per gallon)
Were 23 gallons enough for the round trip ??
If not, how much more gallons, he needs ?? 

  Difficulty Level - 3/5

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  Solution : 

   The trip was a total of 120 kms, which at 8 kms to the gallon, used 15 gallons.
   The outward trip of 60 kms was at 12 kmph, which took 5 hours. 
   The return trip was at 16 kmph, which took 3.75 hours. 
   Which is a total journey time of 8.75 hours, which meant that 8.75 gallons were lost.
   So, 15 gallons were used for the trip, 8.75 gallons were lost, which is a total of 23.75 gallons. 
   So, 23 gallons was not enough for the round trip and he needs 0.75 gallons more.