The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is:
70 km/hr
75 km/hr
84 km/hr
87.5 km/hr

• 87.5 km/hr
  
  The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours,
  then the speed of the first train = 400/4= 100 kms/hr
  
  then the speed of the first train is:100*7/8 = 700/8 = 87.5 km/hr
• 12 years agoHelpfull: Yes(23) No(1)
• 7/8=x/100
  8x=700
  x=87.5kmph
• 10 years agoHelpfull: Yes(6) No(1)
• Let the speed of two trains be 7x and 8x kmph,
  
  Distance travelled by second train= 400km
  Time taken by second train to cover the distance= 4hrs
  
  speed=distance travelled/time taken
  speed of second train=400/4 kmph=100kmph
  
  therefore 8x=100 ==> x=12.5
  speed of first train 7x= 7*12.5= 87.5 kmph
• 10 years agoHelpfull: Yes(5) No(1)
• Speed of first train is 7s
  speed of second train is 8s ----(1)
  According to question
  speed of second train= 400/4=100km/hr-----(2)
  hence ,
  8s=100
  s=12.5
  now speed of first train be= 7s
  =7 (12.5)=87.5km/hr.ans
• 6 years agoHelpfull: Yes(0) No(0)