Solution:

Tank-5

Explanation:
This is a variation of Which Tank Will Fill First Brain Teaser but in this puzzle connection between tank-5 and tank-2 is closed so water will go into tank-5 from tank-1 but not go to tank-2. Therefore tank-5 will be filled first.

Solution:

7

Explanation:
8th is bald man head, check the video below.

Solution:

5

Explanation
First three equation in the image can be written as :
a) 3 BED = 30
b) 2 BED + BUS = 40
c) BED + 2 BUS+ 2 TROPHY = 60

From equation a)
BED = 10

From equation b)
BUS = 40 -20 =20

From equation c)
10 + 40 + 2 TROPHY = 60

TROPHY = 5

Solution:

No wheels which imply car is not moving :-)

Solution:

It can be done as shown below.

Solution:

It can be solved as shown.

Solution:

C

Explanation:
Check the image.

Solution:

Nightmare.

Explanation:
(K)night + mare (A mare is the female of a horse)

Solution:

Difference 1
Toy plane direction is different.

Difference 2
On the clock, number 1 & 2 is missing.

Difference 3
The colors of lamp's light is changed.

Difference 4
The ribbon on the gift is missing.

Difference 5
Duck is added in the gift section.

Solution:

It can be done in 8 moves as shown in the animated image below.