assume that rate of consumption of coal by an engine varies as the square of the speed and is 1000 kg/hr when the speed is 60 km/hr.,when in motion. if the coal costs the railway company rs 15 per 100 kg and the other expenses of running the train is rs 12 per hour, find a formula for the cost in paise per km when the speed is s km per hour.
a)(1200/s)+(25s/6)
b)(1200/s)+(25s^2/6)
c)(1200/s)+(5s^2/18)
d)none

• answer A is correct.
• 9 years agoHelpfull: Yes(2) No(3)
• ans is b
  
  as according to question,
  cost=(1200/s) +((1000/60^2)*s^2*1500/100)
  =(1200/s) +(25 s^2/6)
• 9 years agoHelpfull: Yes(1) No(0)
• could you plz explain ? @Abhishek nkumar
• 9 years agoHelpfull: Yes(0) No(0)
• 1000kg/hr- 60km/hr
  150rs for 1000kg
  12 rs per hour
  162rs for 1000kg/hr at 60km/hr
  substitute s=60 and check the options
• 9 years agoHelpfull: Yes(0) No(0)