A car during its journey travels 1 hour at a speed of 40 kmph, another 30 minutes at a speed of 60 kmph, and 2 hours at a speed of 60 kmph.The average speed of the car is
Choose the correct choice.
A) 63.07 kmph
B) 54.28 kmph
C) 62.02 kmph
D) 64.02 kmph
E) none of these

Rationale: first car travels 1 hrs at speed of 40 kmph distance = 40 x 1 = 40 m then car travels 30 min at a speed of 60 kmph distance = 30 min at speed of 60 kmph distance = 60 x 1 / 2 = 30 m at last it travels 2 hours at speed of 60 kmph distance = 60 x 2 = 120 m total distance = 40 + 30 + 120 = 190 total time = 1 + 1 / 2 + 2 = 3.50 average speed of the car = 190 / 3.25 = 54.28 answer : b
Answer: B