Tim and Elan are 90km away one another . they are starting to move towards each other simultaneously, Tim at a speed of 10 kmph and Elan at a speed of 5 kmph . if every hour they double their speeds, What is the distance that Tim will pass until he meets Elan?
a)45km
b)60km
c)30km
d)80km

• b)60 km
  In 1st hour relative speed Tim(10)+Elan(5)=15 Km/hr.So dist. covered=15Km
  In 2nd hour relative speed Tim(20)+Elan(10)=30 Km/hr, dist. covered=30Km
  Upto 2nd hour total distance covered=45 Km, dist. remained=90-45=45 Km
  In 3rd hour relative speed=Tim(40)+Elan(20)=60 Km/hr
  To cover 45Km time required=45/60=3/4 hour=45 minutes
  So distance covered in the 3rd hour by Tim in 3/4 hr=40*3/4=30 Km
  Therefore total dist. covered by Tim=10+20+30=60 Kms
  
  
• 12 years agoHelpfull: Yes(58) No(8)
• 60 kms
  
  As their speeds are always in ratio of 2:1, distance covered at any time will be in ratio of 2:1.
  To check further
  
  They will met after 2.75 hrs as rel speed in three hrs are 15 km/hr,30 kmph and 60 kmph respectively.
  Distance covered by Tim will be 10+20 + 0.75*40 = 60 kms.
• 12 years agoHelpfull: Yes(24) No(4)
• b)60 km
  since the ratio of their speed remain constant.
  hence we can simply solve it by their initial speed.
  let t be the time of meeting.
  so 10t+5t=90
  on solving t=6
  so distance travelled by tim
  10t=10*6=60.
• 10 years agoHelpfull: Yes(3) No(0)
• b)60 km
  See 10+5 km they cover every hour. At this speed it will take 6 hours to meet. For Tim 10*6= 60. As he covers a distance of 10 km every hour.
• 9 years agoHelpfull: Yes(0) No(0)