Pattern: Time to fill bucket

This is a simple common sense based question:

We will be given a container/vessel/bucket in which liquid is getting doubled after a given time period and we need to find the time to fill it completely.
Example

There are two water tanks A and B, A is much smaller than B. While water fills at the rate of 1 liter 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 liters, second hour it has 20 liters and so on). If tank B is 1/32 filled in 21 hours, what is total duration of hours required to fill it completely?
a) 26 B)25 c)5 d)27

Solution:
Just forget about tank A.
The water in tank B is doubled every hour.
                             1/32 filled in 21 hours (Given)
  =>                       1/16 filled in 22nd hour                     
  =>                       1/8   filled in 23rd hour         
  =>                       1/4   filled in 24th hour         
  =>                       1/2   filled in 25th hour         
  =>                       1      filled in 26th hour          i.e   COMPLETELY FILLED

Answer : option a

Shortcut Method: See the initial state of the tank B as 1/2^5 (1/2^5=1/32)  . Now add this exponent i.e 5 to given hours i.e 21, so ans is 21+5=26 hours.

You can try the questions with similar pattern:

2. There are two pipes A and B. If A filled 10 liters in an hour, B can fill 20 liters in same time. Likewise B can fill 10, 20, 40, 80, 160…... If B filled in 1/16 of a tank in 3 hours, how much time will it take to fill the tank completely?
a) 9 B)8 c)7 d)6

3. There are two water tanks A and B, A is much smaller than B. While water fills at the rate of 1 liter every hour in A, it gets filled up like, 10, 20, 40,80, 160…..in tank B. 1/8 th of the tank B is filled in 22 hours. What is the time to fill the tank fully?
a) 26 B)25 c)5 d)27

4. A tank is filled with water. In first hour 10 liters, second hours 20 liters, and third hour 40 liters and so on…If time taken to fill ¼ of the tank if 5 hours. What is the time taken to fill up the tank?
a) 5 B)8 c)7 d)12.5

5. If a tank A can be filled within 10 hours and tank B can be filled ¼ in 19 hours then, what is the time taken to fill up the tank completely?
a) 21 B)38 c)57 d)76

Pattern: Find unknown x

This type of questions are very simple and require you to fin the value of x by substitution of the given condition:
Example:

1. (1/2) of a number is 3 more than the (1/6) of the same number?
a) 6 b)7 c)8 d)9

Solution:
Let the number be x.
The equation will be:
                               x/2=3+x/6
=> x/2-x/6=3

=> 2x/6=3

i.e x=9 (Option d)

You can try the questions with similar pattern:

2. (1/3) of a number is 3 more than the (1/6) of the same number?
a) 6 b)16 c)18 d)21

3. (1/3) of a number is 6 more than the (1/6) of the same number?
a) 6 b)18 c)36 d)24

4. (2/3) of a number is 4 more than the (1/6) of the same number?
a) 6 b)8 c)36 d)24

5. (1/3) of a number is 5 more than the (1/6) of the same number?
a) 6 b)36 c)30 d)72