the ratio between speed of d 2 trains is 7:8. if d 2nd train runs 400km in 4 hrs, wat is d speed of d 1st train?
a) 85kmph
b) 87.5kmph
c) 90kmph
d) 92.5kmph

• b. 87.5 kmph
  If the speed of the trains are 7x & 8x respectively
  2nd train's speed(kmph)=400/4=100 =8x, x=100/8=25/2
  So 1st train's speed=7x=7*25/2= 87.5
• 11 years agoHelpfull: Yes(18) No(0)
• second train 's speed is 100km/hr. so
  7/8 = x/100 ;
  x = 87.5
  
• 11 years agoHelpfull: Yes(6) No(0)
• speed of 2nd train = 400/4=100kmph
  so speed of first train = 700/8= 87.5
• 11 years agoHelpfull: Yes(3) No(1)
• B- 87.5
  By S=D/T, When T2 travels 400km in 4hr so speed= 100km/h and with 8:7 ratio T1 gets speed of 87.5km/h
• 11 years agoHelpfull: Yes(1) No(0)
• given speed of a and b are in the ratio 7:8 and b'speed =distance/time
  a/b=7/8=>a=7/8*b
  a=(7*400)/(8*4)=87.5kmph
• 11 years agoHelpfull: Yes(1) No(0)
• speed of 2nd train = 400/4 = 100kmph
  hence 7x/100 = 7/8
  => 56x = 700
  => x = 700/56
  => x = 12.5
  so 7x = 7*12.5 = 87.5
• 11 years agoHelpfull: Yes(0) No(0)