Two pipes A and B can fill a tank in 24 min. and 32 min. respectively. If both the pipes are opened simultaneously, after how much time B should be closed so that the tank is full in 18 minutes?

• a 1 day work 1/24
  b 1 day work 1/32
  since the work is completed in 18 min and we have to be closed after some time ,pipe a fill pipe for whole 18 min ,a 18 min work is 18/24=3/4
  remaining work 1/4 which is completed by b
  so b should be closed after 32/4=8 min
• 9 years agoHelpfull: Yes(11) No(0)
• x(1/24+1/32)+(18-x)1/24=1
  ans=8min
• 9 years agoHelpfull: Yes(6) No(1)
• after 8 min
• 9 years agoHelpfull: Yes(3) No(2)
• let size of tank=96m (lcm of 24 & 32) , then speed of A for 1min=96/24=4m/min & B=96/32=3m/min
  then when both pipes are opened speed is=3+4=7m/min
  let Xm tank is filled when both pipes are opened & (96-X)m tank is filled when only pipe A is opened..
  X/7+(96-X)/4=18
  so X=56, then 56/7 time pipe B is opened... i.e 8 min & after 8min pipe B is closed
  so pipe A required (96-56)/4=10min
  total=10+8=18
  ans.=8min
• 9 years agoHelpfull: Yes(3) No(0)
• let size of tank=96m , then speed of A for 1min=96/24=4m/min & B=96/32=3m/min
  then when both pipes are opened speed is=3+4=7m/min
  let Xm tank is filled when both pipes are opened & (96-X)m tank is filled when only pipe A is opened..
  X/7+(96-X)/4=18
  so X=56, then 56/7 time pipe B is opened... i.e 8 min & after 8min pipe B is closed
  so pipe A required (96-56)/4=10min
  total=10+8=18
  ans.=8min
• 9 years agoHelpfull: Yes(1) No(0)
• let a and b work together for x mins
  a 1 min work=1/24
  b 1 min work=1/32
  a+b 1 min work=1/24+1/32=7/96
  a+b x min work=7x/96
  as given,7x/96+(18-x)*1/24=1
  x=8 min
  
• 8 years agoHelpfull: Yes(1) No(0)
• a completed work in 18 min=18/24=3/4
  So remaining work=1-(3/4)=1/4
  x((1/24)+(1/32))=(1/4)
  then we will get x=24/7 then and:24/7
• 9 years agoHelpfull: Yes(0) No(2)
• explain it clearly
• 9 years agoHelpfull: Yes(0) No(0)
• thnk u@ swapnali pawar
• 9 years agoHelpfull: Yes(0) No(0)
• let a and b work together for x mins
  a 1 min work=1/24
  b 1 min work=1/32
  a+b 1 min work=1/24+1/32=7/96
  a+b x min work=7x/96
  as given,7x/96+(18-x)*1/24=1
  x=8 min
  
• 8 years agoHelpfull: Yes(0) No(0)
• 6 minutes...A=1/24,B=1/32
  K(1/24+1/32)+18*1/32=1
  K=6
• 8 years agoHelpfull: Yes(0) No(0)