A car during its journey travels 30 minutes at a speed of 60 kmph, another 45 minutes at a speed of 80 kmph, and 1 hours at a speed of 70 kmph.The average speed of the car is  Choose the most appropriate option:
A) 63.07 kmph  B) 64 kmph  C) 75 kmph  D) 80 kmph  E) None of these
First car travels 30 min at speed of 60 kmph   distance = 60 x 1/2 = 30 m   Then car travels 45 min at a speed of 80 kmph   distance = 45 min at speed of 80 kmph   distance = 80 x 3/4 = 60 m   at last it travels 1 hours at speed of 70 kmph   distance = 70 x 1 = 70 m   Total distance = 30 + 80 + 70= 
<gadget id="calculator">30 + 80 + 70</gadget>
<output>180</output>
180   Total time= 1/2 + 3/4 + 1= 
<gadget id="calculator">1/2 + 3/4 + 1</gadget>
<output>9/4 = around 2.25</output>
2.25   Average speed of the car= 180/2.25= 
<gadget id="calculator">180/2.25</gadget>
<output>80</output>
80   ANSWER:80 kmph
<result>D</result>
A car during its journey travels 30 minutes at a speed of 60 kmph, another 45 minutes at a speed of 80 kmph, and 1 hours at a speed of 70 kmph.The average speed of the car is