There are two pipes A and B. If A fills 10 litres per hour, B’s filling rate doubles after every hour starting with 10 litres in first hour (i.e. 10, 20, 40, 80, 160 litres and so on per hour). If B filled in 1/16 of a tank in 3 hours, how many hours will it take to fill the tank completely?
a) 9
b) 18
c) 27
d) 46
e) None of these

• 1/16-------3 hr,
  1/8---------4,
  1/4---------5,
  1/2---------6,
  1------------7. therefore ans is (e)NOT
• 10 years agoHelpfull: Yes(14) No(4)
• Let the total capacity of the tank be x litre
  thus ,
  1/16 * x=40
  
  => x=640 litres
  thus the total capacity of the tank is 640
  therefore...
  5hr--------------160 litre
  6hr--------------320 litre
  7hr--------------640 litre
  
  In 7 hr the tank will be full,hence the ans is option e(none of these)
  
  
  
• 10 years agoHelpfull: Yes(13) No(4)
• ans : 6 hour 46 min
  1/16th of the tank is equals to (10+20+40)=70 ltr
  hence, full tank is of 70*16=1120ltrs.
  1st hour 10ltr
  2nd hour 20ltr =>30
  3rd hr 40 ltr=>70ltr.....
  (10+20+40+80+160+320)=630ltr
  remaining 1120-630=490ltr
  in this hour the pipe will fill 640ltr so for 490 it will take 45.93min
  hence total time 6hr 46min
• 10 years agoHelpfull: Yes(10) No(1)
• IN 3 hours starting 10L per hour
  10,20,40
  which equals to 70
  now A fils 10L per hour so it will take 7 hours to fill 1/16 of the tank
  so to fill the full tank it fill take 7*16=112 hours which means 1120L
  so for B
  10 ..............1hr
  20................2hr
  40
  80
  160
  320
  640
  1280.........8hr
  so it will fill before 8 hours
  so ans is e
• 10 years agoHelpfull: Yes(5) No(0)
• please anyne give the proper explaination of that answer
• 10 years agoHelpfull: Yes(2) No(0)
• e) None of these
  
  In 3 hrs, B can fills 10+20+40=70 litres, which is 1/16 of the total capacity, so total capacity of tank=70*16=1120 litres.
  Filling at the end of
  1 st hour= 10 + 10 =20 litres
  2nd hour=10 + 20 =30 litres
  3rd hour=10 + 40 =50 litres
  4th hour=10 + 80 =90 litres
  .
  .
  Thus we observe that filling is 20, 30, 50, 90, 170, 330, 650,...litres in 1,2,3,4,5,6,7, ... hours respectively.
  Sum of 20+30+50+90+170+330 =690 litres is the filling at the end of 6 hrs and for remaining (1120-630) =490 litres can be filled in next 1 hour which can add 650 litres.
  So in 7th hour adding tank will be completely filled.
• 7 years agoHelpfull: Yes(2) No(0)