A & B start towards each other. dist. between them 90km. A's speed=10km/h B's speed=5km/h. every hour the speed gets doubled. How much distance will A cover before meeting B?

• In 1st hour, A covers 10 Km. and B covers 5 Km.
  In 2nd hour, A covers 20 Km. and B covers 10 Km.
  So, total distance covered by A and B = (30+15)Km. = 45 Km.
  Remaining distance = (90-45) Km. = 45 Km.
  Now, speed of A = 40 Km/hr and speed of B = 20 Km/hr
  If A covers x Km. more before meeting B, then B must be covering (45 - x) Km. before meeting A. The time required by them to do so must be same.
  Therefore, x/40 = (45 - x)/20
  x = 30 Km.
  So, distance covered by A before meeting B = (30+30) Km. = 60 Km.
• 9 years agoHelpfull: Yes(8) No(0)
• 60 Km.
  
  Time after which they will meet each other=90/(10+5)= 6 hr.
  So distance covered by A in 6 hr.=10*6=60 Km.
• 9 years agoHelpfull: Yes(2) No(5)
• 60 km
  when dist traveled by A = 10 @ 10km/hr, B = 5 @5km/hr
  when dist traveled by A = 20 @20km/hr, B = 10 @10 km/hr
  total = 45
  now break 40 into 4 and 20 into 4 parts
  now
  when dist traveled by A = 10, B = 5
  when dist traveled by A = 10, B = 5
  when dist traveled by A = 10, B = 5 ,they will meet at this point.
  there fore distance traveled by A = 10+10+10+20+10 = 60km
• 9 years agoHelpfull: Yes(1) No(0)
• Ans:60km
  1'st hour
  A moves 10km B moves 5km (total movement in 1's hour= 10+5=15km)
  2'nd hour
  A moves 20km B moves 10km (total movement in 2'nd hour= 20+10=30km)
  after 2 hours the overall movement =15+30=45km
  distance left=90-45=45km
  now , in 3'rd hour
  A' s speed=40 and B's speed=20
  from here we can say that they will meet in more than 2 hours but less than 3 hours with speed=40 and 20,at that moment the distance between A and B is=45km
  their relative speed=40+20=60km/h
  time taken to cover remaining 45km with relative speed=45/60 =0.75 h
  in 0.75 h , A moves=0.75*40=30km
  so, A's total movement before meeting to B is=10+20+30=60km
  
  
  
  
• 9 years agoHelpfull: Yes(0) No(0)
• ans-60km
  solu- in the first hour a and b will cover 10 and 5 kms resp.
  now their speed will double so they will cover 20 and 10 resp.
  total distance covered by them till now is 45
  rest 45 kms they can will travel depending upon their relative speed. hence the time taken to cover 45 km more = 3/4 hr
  distance covered by a in that = (3/4)*40 = 30.
  total distance covrd by a = 10+20+30=60
• 9 years agoHelpfull: Yes(0) No(0)
• in first hour they will cover distance=15
  2nd hour ...........................................=30
  remaining 45 km will cover with the speed of (40+20) km/hr= 45mins
  so they will meet after 2hours and 45 mins
  A covers the distance before meeting = 10+ 20+ 30=60 km
• 9 years agoHelpfull: Yes(0) No(0)
• 66.66 km
  please see carefully
  1st hour they cover =15km
  2nd hour speed double they cover=30km (A=10km/h,B-5kmh
  than remaining distance is =55km' (A=20kmh,B=10kmh)
  speed double A=40km/h and B=20km/h
  than time =55/60;
  time =.91.
  distance cover by A= .9*40
  =36.66
  total distance cover by A=30+36.66
  =66.66
• 9 years agoHelpfull: Yes(0) No(2)
• In the first hour A will cover 10km and B will cover 5km. Distance left=75km.
  Speed of A=20km/hr, B's =10km/hr.
  in 2nd hour A will cover 20 km and B will cover 10km. distance left=75-30=45km.
  now A's speed=40km/hr, B's=20km/hr.
  In next 45 mibutes,
  A will cover 30km and B will cover 15km , distance left=45-30-15=0km.
  Distance travelled by A=10+20+30=60km.
• 9 years agoHelpfull: Yes(0) No(0)
• answer is 60
  
• 9 years agoHelpfull: Yes(0) No(0)
• 60 km .. bcz the travel for 2 and 45 m
• 9 years agoHelpfull: Yes(0) No(0)
• as the speed get double every hour but the ratio of their speed will be always constant .
  speed of a:speed of b=2:1
  let a's speed be 2x so b's will be x
  now let a travells d distance so distance travelled by b =90-d
  they meet at time t
  d/2x=90-d/x
  dx=180x-2dx
  dx=180x
  d=60
• 9 years agoHelpfull: Yes(0) No(0)