Solution:

The answer is shown in the below picture

Solution:

Seven

Explanation:
5(dead) + 1(Alive) + 1(you)

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:

The two bars are equal in length.

Explanation:
It's an optical illusion that makes you believe that bar A is longer because of the railway tracks.

Solution:

40 or 96

Explanation:
Solution A :
Add the rhs of the last line to the current line
1 + 4 = 5
5 + 2 + 5 = 12
12 + 3 + 6 = 21
21 + 8 + 11 = 40

Solution B :
RHS = 1ST NUMBER + (1ST NUMBER * 2ND NUMBER)
1 + (1 x 4) = 5
2 + (2 x 5) = 12
3 + (3 x 6) = 21
8 + (8 x 11) = 96

Solution:

3

Explanation:
Note: Glass 5 6 and 7 not possible as there is a blocked connection.
Now, as the connection to 3 is lower than that of 2, it will fill first while rest beer glasses will remain empty.

Solution:

3 and 7

Explanation:
Painters 3 and 7 are the only painters that match all nine circled areas.

Solution:

It can be done as shown in the picture below.

Solution:

Six item that does not belong to this era are :
1. Plane
2. Table lamp.
3. Scooter.
4. Sunglasses.
5. Earphones
6. Mobile phone.

Solution:

797

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