A square is of side 1 km. A man travels first 2 sides with the 30 mph and third side with 60 kmph. What is the speed that man has to travel the fourth side if the average speed is 60 kmph

• i mile =1.6km,
  let the speed of the man reqd. to cover the 4th side be x,
  now, avg speed = (total distance covered/ total time taken)
  total distance covered = 4 kms
  total time taken:
  time taken during first 2 sides = 2km/48kmph (30mph=48kmph)
  time taken during third side = 1km/60kmph
  and time taken during 4th side = 1km/xkmph
  
  therefore avg speed= 4/((2/48)+(1/60)+(1/x))= 60 (given)
  solving it for x we get 16x = 14x+240
  i.e, 2x = 240
  
  
• 10 years agoHelpfull: Yes(47) No(4)
• 1 Mile= 1.6 Km
  Total time taken to travel 3 sides =(1/48)+(1/48)+(1/60)= 7/120 hr
  time taken to travel 4 sides at avg speed= 1/15 hr
  So, reqred speed for fourth side= 1/{(1/15)-(7/120)}= 120 Kmph :)
• 10 years agoHelpfull: Yes(41) No(10)
• ans : 179.94km/hr
  let the speed of man to travel the 4th side be x
  average speed = (0.03+0.03+60+x)/4
  60 = (60.06+x)/4
  60.06+x = 240
  x = 179.94km/hr
• 10 years agoHelpfull: Yes(27) No(36)
• 30+30+60+x/4=60
  solving,
  x=120km/hr
• 10 years agoHelpfull: Yes(21) No(21)
• 1 mile= 1.6 km therefore 30 mph= 48 kmph. now time taken to travel first side= 1/48,time taken to travel 2nd side= 1/48,time taken to travel 3rd side =1/60.
  answer is 120 kmph.
  let he travel fourth side with the speed of x kmph. time taken to travel 4th side =1/x. so total time= 1/48 + 1/48 + 1/60 + 1/x. total distance= 1+1+1+1=4. so average speed = total distance/total time or 60= 4/(1/48 + 1/48 + 1/60 + 1/x). on solving we get x= 120 kmph.
• 10 years agoHelpfull: Yes(13) No(1)
• 1/48+1/48+1/60+x
  x=120
• 10 years agoHelpfull: Yes(8) No(0)
• since given for 2 sides it is 30,3rd side 60 and 4th side let say x.
  now,we know how to take average=(30+30+60+x)/4=60.since average speed is given.
  mow solve it (120+x)/4=60
  120+x=240
  x=120
  answer is 120
  
• 10 years agoHelpfull: Yes(5) No(3)
• answer 84 kmph
  1 mile = 1.6km
  so therefore
  30 mile = 48 km
  so 30 mph =48 kmph
  now let fourth side speed is x
  so average speed of first side and second side and third side is 48 ,48 ,60 in kmph respectively .
  (48 +48 +60 + x )/4 = 60
  after solving we get x= 84kmph
• 10 years agoHelpfull: Yes(4) No(13)
• average speed = total distance/ total time
  4/ ((2/1.6*30) + (1/30)+ (1/x))
  from here x = 120kmh
• 10 years agoHelpfull: Yes(4) No(1)
• 1 Mile= 1.6 Km
  average speed = total distance traveled by person or thing / total time taken
  60 = 4 / (1/48 + 1/48+ 1/60 + 1/x)
  x=120
• 10 years agoHelpfull: Yes(2) No(0)
• let, abcd be a square. ab=bc=cd=da=1km... 30mph=48kmph ( 1m=1.6km), 60mph=96kmph. abcd=4km.By arranging the equations, we get, (1/48)+(1/48)+(1/96)+(1/x)=(4/60) , where x is the required answar.... after solving this equation, we get, x is nearly equal to 42.86mph or 68.57kmph... thank you...
• 10 years agoHelpfull: Yes(1) No(4)
• 1 Mile= 1.6 Km
  Total time taken to travel 3 sides =(1/48)+(1/48)+(1/60)= 7/120 hr
  time taken to travel 4 sides at avg speed= 1/15 hr
  So, reqred speed for fourth side= 1/{(1/15)-(7/120)}= 120 Kmph :)
• 10 years agoHelpfull: Yes(1) No(0)
• 120 kmph.. i think
  stotal=s1+s2+s3+s4%4
  
  
  
• 10 years agoHelpfull: Yes(1) No(0)
• given s1+s2+s3+s4/4=60,
  30+30+60+s4=60*4,
  s4=120 kmph
• 10 years agoHelpfull: Yes(1) No(0)
• 1 mile=1.6 km
  30 mile=48 km
  let,speed=x kmph
  1/48+1/48+1/60+1/x=4/60
  x=120
• 9 years agoHelpfull: Yes(1) No(0)
• 179.94 kmph
• 10 years agoHelpfull: Yes(0) No(4)
• let the speed of man to travel the 4th side be x km/hr.
  average speed=(0.03+0.03+60+x)/4
  60=(60.06+x)/4
  x=179.94 km/hr
• 10 years agoHelpfull: Yes(0) No(2)
• ans:179.94
  60= (1/2+1/2+60+x)/4
  x=179.94
• 10 years agoHelpfull: Yes(0) No(2)
• 1 mile=1.6km => 30miles=30*1.6= 48km.
  (48+48+60+x)/4=60kmph
  => x=240-156= 84kmph.
  84kmph is the right answer.
  If the answer is 120kmph as many have said, then the average of all the speeds doesn't yield 60kmph,thus not satisfying the given condition.
• 10 years agoHelpfull: Yes(0) No(1)
• 30 mile = 48 km
  (48+48+60+x)/4 = 60
  156 + x = 60 X 4
  x = 240 - 156
  x = 94 kmph
• 10 years agoHelpfull: Yes(0) No(1)
• let 4 sides be a,b,c,d
  a+b+c+d/4=60
  30+30+60+d/4=60
  30+30+60+d=240
  120+d=240
  d=240-120
  d=120 mph
• 10 years agoHelpfull: Yes(0) No(1)
• (1/48)+(1/48)+(1/60)= 7/120 h
  
  Ans 120
• 9 years agoHelpfull: Yes(0) No(0)
• (2*30+60+x)/4=60,
  x=120
• 9 years agoHelpfull: Yes(0) No(0)
• avg 60={4/(x+1/48+1/48+1/60)}
  x=1/120
  so 4th side speed=1/(1/120)=120 ans.
• 9 years agoHelpfull: Yes(0) No(0)
• 1 mile=1.6 km
  30 mile=48 km
  let,speed=x kmph
  1/48+1/48+1/60+1/x=4/60
  x=120
• 9 years agoHelpfull: Yes(0) No(0)
• 1 mile=1.6 km
  30 mile=48 km
  let,speed=x kmph
  1/48+1/48+1/60+1/x=4/60
  x=120
• 9 years agoHelpfull: Yes(0) No(0)
• 1 mile=1.6 km
  30 mile=48 km
  let,speed=x kmph
  1/48+1/48+1/60+1/x=4/60
  x=120
• 9 years agoHelpfull: Yes(0) No(0)
• 1 mile=1.6 km
  30 mile=48 km
  let,speed=x kmph
  1/48+1/48+1/60+1/x=4/60
  x=120
• 9 years agoHelpfull: Yes(0) No(0)
• 1 mile=1.6 km
  30 mile=48 km
  let,speed=x kmph
  1/48+1/48+1/60+1/x=4/60
  x=120
• 9 years agoHelpfull: Yes(0) No(0)
• 1 mile=1.6 km
  30 mile=48 km
  let,speed=x kmph
  1/48+1/48+1/60+1/x=4/60
  x=120
• 9 years agoHelpfull: Yes(0) No(0)
• the answer is 120 because (AVERAGE =SUM/N)........(30+30+60+120)/4=60
• 9 years agoHelpfull: Yes(0) No(0)
• Let x be the speed of travelling 4th side.
  so,according to ques.
  we may write,
  (30+30+60+x)/4=60
  x=120 kmph
• 9 years agoHelpfull: Yes(0) No(0)
• first two sides speed=30 mph=30/1000 kmph
  3rd side speed =60 kmph
  let 4th side speed =x kmph
  and given that avg spd=60 kmph
  so
  (30/1000+60+x)=60
  x=119.97~120 kmph ans
  
• 9 years agoHelpfull: Yes(0) No(0)
• speed of first 2 sides=30 mph=30/1000 kmph
  speed of third side =60 kmph
  now,
  let speed of forth side is x= kmph
  so,
  2*30/1000+60+x=60..... on solving this equation
  x=179.94 kmph ans
• 9 years agoHelpfull: Yes(0) No(1)
• Avg speed = sum of speeds/no of speeds
  (30+30+60+x)/4 =120
  X=120
• 8 years agoHelpfull: Yes(0) No(0)
• square has 4 sides right so
  let's consider speed of fourth side is x
  now calculate average of 4 sides =(30+30+60+x)/4
  =120 kmph
• 8 years agoHelpfull: Yes(0) No(0)