in the question,A ^ B refers to a raised to power of B
assume that the rate of consumption of coal by a locomotive engine varies as the square of speed and is 1000 kg per hour when the speed is 60 km per hour, when in motion. if coal costs the railway company Rs 15 per 100 kg and if the other expenses of running the train is Rs 12 per hour. find the formula for the cost in paise per km when the speed is S km per hour:
a)(1200/s) + (25 S/6)
b) none of these
c)(1200/S) +(5 S^ 2/18)
d)(1200/S)+(25 S^2/6)

• given coal_consumption/hour proportional to speed^2.
  Hence coal_consumption/hour = k.(speed^2)
  dividing both sides by speed => coal consumption/km=k*speed
  k=5/18 ( found out by given condition of 1000=k.(60)^2 )
  k*speed*1500/100=(25*Speed)/6 (i)
  and 1200/s = Other expenses per km. (ii)
  
  Adding i and ii , answer is option A !
  
  ( time/speed always yields distance )
• 9 years agoHelpfull: Yes(10) No(5)
• For this qus ans are given like this a)7 b)6 c)0 which is correct option
• 8 years agoHelpfull: Yes(3) No(0)
• please can you explain this answer clearly
• 9 years agoHelpfull: Yes(2) No(1)
• as per the first statement: r=(ks)^2 so r=1000,s=60 then k^2=5/18
  
  total cost=12*100/s(100 for paise)+(5/18s^2)/s*15
  cost=1200/s+25s/6 i.e option A
  ANS:A
• 9 years agoHelpfull: Yes(1) No(4)
• Please explain clearly.Solutions are not clear
• 9 years agoHelpfull: Yes(1) No(0)
• please explain the solution clearly
  
• 9 years agoHelpfull: Yes(1) No(0)
• Answer is D(after solving). coal consumption depends on s^2 so answer will be C Or D only
• 8 years agoHelpfull: Yes(0) No(0)