Q. A car covers a distance of 715 km at a constant speed. If the speed of the car would have been 10 km/hr more, then it would have taken 2 hours less to cover the same distance. What is the original speed of the car?

Option
a) 45 km/hr
b) 50 km/hr
c) 55 km/hr
d) 65 km/hr

• 715 = (x + 10)[(715/x) - 2]
  
  715 = 715 - 2x + (7150/x) - 20
  or
  2x^2 + 20x - 7150 = 0
  x^2 + 10x - 3575 = 0
  
  (x + 65)(x - 55) = 0
  x = 55 km/hr
• 11 years agoHelpfull: Yes(0) No(0)
• original speed = 55 kmph
  
  715 =55*13=65*11
• 11 years agoHelpfull: Yes(0) No(0)
• (x + 65)(x - 55) = 0
  x = 55 km/hr
  
• 10 years agoHelpfull: Yes(0) No(0)
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• 5 years agoHelpfull: Yes(0) No(0)
• original speed = x
  715/x - 715/(x+10) = 2
  on solving x= 55 km/hr
• 5 years agoHelpfull: Yes(0) No(0)