A tank is filled in 10 hours by three pipes A, B and C. The pipe C is twice as fast as B and B is twice as fast as A. How much time will pipe A alone take to fill the tank?
A. 70 hours
B. 30 hours
C. 35 hours
D. 50 hours

• 1/A + 1/B + 1/C = 1/10 ( a, b and c 1 hour work)
  given.. 1/B= 2/A and 1/C = 2/B = 4/A
  hence 1/A + 2/A + 4/A = 1/10
  on solving.... we get 1/A = 1/70 ( work done by A in 1 hour)
  therefore time taken by A is 70 hours to finish the whole work
  
• 10 years agoHelpfull: Yes(31) No(0)
• C is twice as fast as b
  so time taken by b:c is b:b/2
  b is twice as fast as a
  so time taken by a:b is a:a/2
  
  time taken by a:b:c is a:a/2:a/4
  
  a+b+c fill the tank in 10 hrs...
  so in 1 hr they can fill
  
  1/a+2/a+4/a=1/10
  
  7/a=1/10
  a=70hrs
  
  Ans : A can fill the tank alone in 70hrs
  
  
• 10 years agoHelpfull: Yes(9) No(0)
• A+B+C 'S 1 HR WORK = 1/10
  B=2A C=2B=4A
  SUBSTITUTE THESE VALUES
  SO A+2A+4A=1/10
  7A=1/10
  :::: A=1/70 SO TIME TAKEN=70hrs
• 10 years agoHelpfull: Yes(6) No(0)
• let A take =x hr
  B=x/2
  c=x/4
  x+(x/2)+(x/4)=10
  x=70
• 10 years agoHelpfull: Yes(5) No(9)
• given that A+B+C=10
  c=2b;
  b=2a;
  by substituting them in eq 1
  a+2a+2(2a)=7a
  7(10)=70
  
• 9 years agoHelpfull: Yes(1) No(0)
• 70 ahihi;pou[ouo
• 10 years agoHelpfull: Yes(0) No(2)
• option A.
  70 hrs
  
• 10 years agoHelpfull: Yes(0) No(1)
• let the speed of a tank be x ,,then acc. to question b =x/2 and c =x/4 ,
  
  thn part filled by a,b and c in 1 hour =1/10
  
  1/x+ 2/x+ 4/x = 1/10 => x=70 ,,ans =70 .........RAhul verma
• 10 years agoHelpfull: Yes(0) No(0)
• 1/A + 1/B + 1/C = 1/10 ( a, b and c 1 hour work)
  given.. 1/B= 2/A and 1/C = 2/B = 4/A
  hence 1/A + 2/A + 4/A = 1/10
  on solving.... we get 1/A = 1/70 ( work done by A in 1 hour)
  therefore time taken by A is 70 hours to finish the whole work
• 9 years agoHelpfull: Yes(0) No(0)
• 1 hour work is
  1/A + 1/B + 1/C = 1/10
  Given: 1/B= 2/A and 1/C = 2/B
  =>1/C = 4/A
  on putting the values, we get
  1/A + 2/A + 4/A = 1/10
  =>1/A = 1/70
  Since,work done by A in 1 hour =1/70
  therefore time taken by A to finish the whole work is 70 hours
• 9 years agoHelpfull: Yes(0) No(0)
• as we know time*area=constant
  let area of a=x
  so 10 hours*(x+2x+4x)=time*x
  10*7x=time*x
  time=70 hours
• 9 years agoHelpfull: Yes(0) No(0)
• A+B+C=110
  2B=C
  B=2A
  so,2B=2(2A)
  2B=4A
  A+2A+4A=170
  ANS= 70hour
• 9 years agoHelpfull: Yes(0) No(0)
• 6^n=1st digit is 6
  17^3*17^3= 1st digit is 1.
  6+1=7/7=1
• 9 years agoHelpfull: Yes(0) No(0)
• b=2a
  c=2b=4a
  1/a+2/a+4/a=1/10
  a=70
  
• 7 years agoHelpfull: Yes(0) No(0)
• work done for 1 hour:1/A+1/B+1/C=1/10.......eq1
  1/C=2/B,1/B=2/A
  substitute in eq1 we get
  1/A+2/A+2/B=10
  Again substituting these values we get
  1/A+2/A+4/A=1/10
  7/A=1/10
  so a takes 70hours
• 3 years agoHelpfull: Yes(0) No(0)