A and B run 1000 meter race. If A gives B a start of 50 meter,A wins by 40 second. If B gives start of 20 seconds B wins by 20 meter.Find time taken by A to complete race

• Bhai miraj ansari...hw can a person run 1000 m in 4.05 s.. is there ny person faster than usian bolt
• 9 years agoHelpfull: Yes(12) No(4)
• Let A & B take t1 & t2 time to complete race respectively.
  1000/t1 =(1000-20)/(t2+20)----eq1 (For A speed same)
  
  1000/t2 =(1000-50)/(t1+40)--- eq2 (For B speed same)
• 9 years agoHelpfull: Yes(6) No(5)
• a/c to Q A will complete 50m in 40 sec
  so speed of A is 5/4 m/sec
  hence time to complete 1000m race
  time taken by A is =1000/5/4
  =1000*4/5=800 sec
  so time to complete 1000m by A is 800 sec.
• 9 years agoHelpfull: Yes(2) No(0)
• In first case A gives B a start of 50 meter,A wins by 40 second
  so the eq.like this
  let s be speed of B
  1000=950-40s.....[1]
  If B gives start of 20 seconds B wins by 20 meter
  
  so 20=980-20s......[2]
  Divide [1] by [2]
  
  we get s=4.11 m/sec
  in minute= 4.11*60=246.8 m/mint=speed of B
  
  so time taken by B =1000/246.8= 4.05 sec
  
  time taken by B =950/246.8= 3.84 sec
  Ans
• 9 years agoHelpfull: Yes(1) No(9)
• Process of solving From these four digits '0' cannot be at first place to form four digit number so we have 1, 2, or 3 can be at thousand's place keeping one digit at thousand place can have 6 different four digit number so that means 1000*6 + 2000* 6 + 3000* 6 = 36000 Now come to hundred's place we can have all four digit at this place , '0' will not contribute any thing to sum so in all four digits number 1,2,3 will be at 4 times on same place so that means 100*4 + 200* 4 + 300 * 4= 2400 Now come to tenth's place ...same as hundred so 10*4 + 20*4 + 30*4= 240 same for unit place 1*4 + 2*4 + 3*4= 24 in last if you add whole the total sum of all possible four digit number formed is 38664
• 9 years agoHelpfull: Yes(0) No(2)
• A/1000=B/950-40 .....EQN 1
  B/1000 +20=A/980 .....EQN 2
  FROM 1 A=1000(B/950-40)
  PUTTING VALUE OF A ON EQN 2
  B/1000 +20=1000/980(B/980 -40)
  B=38395.7962
  PUTTING VALUE OF A IN EQN 1
  A=416.62SEC
• 9 years agoHelpfull: Yes(0) No(0)
• 21.somthing seconds
• 9 years agoHelpfull: Yes(0) No(0)
• let assume that A and B take x sec and y sec respc. for 1000mtr.
  now,
  x+40=950y/100.................(1)
  and
  980x/1000+20=y............(2)
  solving 1 and 2 we get, x and y..
• 9 years agoHelpfull: Yes(0) No(0)