If Dev walks 30 miles/hr. he reaches 1 hour before and if he walks with a speed of 20 miles/hr. he reach 1 hour late. Find the distance between 2 points and the exact time of reaching destination is 11 am then find the speed with which he walks.

a. 120 miles and 25 miles/ hr.
b. 120 miles and 24 miles/hr.
c. 150 miles and 28 miles/hr.
d. 150 miles and 25 miles/ hr.

• suppose if it takes x hr to reach there. then acc to cond
  30*(x-1)=20(x+1) x=5
  distance= 30*(5-1)= 120 miles
  speed= 120/5 = 24 miles/hr
• 9 years agoHelpfull: Yes(38) No(0)
• B.120 miles and 24 miles/hr
  let the distance be x
  so, x/30=t-1 and x/20=t+1
  => x/30+1=x/20-1
  => x=120 miles
  t=5 hours
  speed=24 miles/hour
• 9 years agoHelpfull: Yes(6) No(0)
• trying with options-
  d=120,t1/120/30=4,t2=120/20=6,tm=120/25=5
  which satisfies the conditions in the problem completely.
  at 30k he reaches 1 hr early at 20k he reaches one hour late.
• 9 years agoHelpfull: Yes(2) No(0)
• B. 120 miles and 24 miler per hour.
  
• 9 years agoHelpfull: Yes(2) No(0)
• Time diff b/w 2 speeds =2hr
  Let dis be x
  So x/20-x/30=2hr
  X=120miles
  Since dist is same so avg speed is
  2*30*20/30+20=24miles/hr
  
  Option b
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• b) 24mph and whatever is the distance
  
• 9 years agoHelpfull: Yes(0) No(0)
• A option
  30t-30=d; 20t+20=d => d=120miles
  Since if he walks 30mph reaches 1 hr before and if he walks 20mph he reaches one hr late so we will take the average value that is 25 to reach on time.
• 9 years agoHelpfull: Yes(0) No(0)
• Suppose he take t time at speed of 30mile/hr.
  now change in speed is = 2/3of previous speed.
  when distance is constant speed is inversely proportinal to time.
  thus time taken at speed of 20 miles/hr = 3/2t.
  
  now we can say that 3/2t-t=2hrs
  t=4 hrs
  distance= speed * time= 30*4= 120 miles/hr.
  he reaches one hour earlier at the speed of 30 miles/hr. it means exact time taken by him is 5 hr.
  
  Thus speed = 120/5= 24 miles/hr.
• 9 years agoHelpfull: Yes(0) No(0)
• I THINK VERIFYING THE OPTIONS IF 120 MILES IS TAKEN
  THEN 120/30=4 HRS
  SIMILARLY 120/20=6 HRS NOW
  120/24= 5 HRS THAT MEANS DEV IS STARTING BY 6 AM IN THE MORNING AND REACHES BY 5 HRS IE 11AM WHERE AS IF HE TRAVEL WITH 30 MILES SPEED HE WILL REACH BY 10AM AND IF HIS SPEED IS 20 MILES THEN HE WILL REACH BY 12 PM SO THE ANSWER IS 120 MILES AND 24 MILES
• 9 years agoHelpfull: Yes(0) No(1)
• Let the be t than we can find time by substituting the value of t And by solving we can find distance which is 120miles Now if the exact time is 110am than By comparing the time we got earlier it is found that The exa t timing of reaching is 5 hrs so now we have distance and exact time We can conclude that the speed is 24miles per hr ans is B
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• answer will be B
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