Solution:

It can be done as shown below.

Solution:

8 Steps

Explanation:
Steps------2L Gallon-------5L Gallon
A-------------12-------------0
B-------------07-------------5
C-------------07-------------0
D-------------02-------------5
E-------------02-------------0
F-------------00-------------2
G-------------12-------------2
H-------------09-------------5

Solution:

797

Explanation:
797 is a prime number
79 is a prime number
7 is a prime number

Solution:

7

Explanation:
Put batteries into 3 groups: two groups of 3 and one group of 2.
It guarantees at least one of the group has got two working battery
Group of 3 requires 3 attempts to verify if 2 batteries of the group are working (B1+B2, B2+B3, and B1+B3) while the group of 2 requires one attempt (B1+B2)
Total attempts = 3 + 3 + 1 = 7

Solution:

16

Watch Video for more explanation.

Solution:

Since the beer bottle is closed, No glass will Ever fill.

The video-version of the puzzle is added below.

Solution:

0.

Explanation:
He scores at least 4 goals --- False
He scores less than 4 goals --- True
He scores at least 1 goal. --- False

Solution:

Samuel should have come at 8 pm but he came home at 8:05 a.m i.e the next day.

Solution:

Red or Tan

Explanation:
The numbers of letters in each color get reduced by one on every row.
Scarlet = 7
Orange and Yellow = 6
Green, Brown, and black = 5
Gray and Blue = 4
So the next color should be of three words like Red or Tan.

Solution:

The girl sitting on your lap.