There are two water tanks A and B,A is much smaller than B.while water fills at the rate of one litre every hour in A,it gets filled up like 10,20,40,80,160...in tank B.(at the end of first hour,B has 10 litre.second hour it has 20,and so on).if 1/32 of B's volume is filled after 3 hours,what is the total duration required to fill it completely?(a)10hours(b)9hours(c)8hours(d)7hours

• for such type of question,
  if 1/(2^n) part is filed up in t hrs
  then it will be fully filled up in (t+n)hrs.
  
  So, here 1/32 i.e. 1/(2^5) is filled up in 3 hrs.
  required time=5+3=8hrs
  
  option (c) is correct
• 13 years agoHelpfull: Yes(10) No(0)
• total volume of tank=32*40=1280
  10,20,40,80,160,320,640,1280 sequence after every hourr
  i.e 8 hours
• 13 years agoHelpfull: Yes(4) No(1)
• let the duration to fill the tank be x hrs.
  nw,x/32 is filled in 3 hrs.nxt hr it will be doubled,so 2*x/32=x/16 will be filled in 4 hrs. likewise,x/8 in 5 hrs,x/4 in 6 hrs,x/2 in 7hrs and x in 8th hr.
  so ans is c
• 13 years agoHelpfull: Yes(4) No(0)
• 8 hrs
• 13 years agoHelpfull: Yes(3) No(0)
• 9
• 13 years agoHelpfull: Yes(0) No(5)