Solution:

There can be various solutions. Here are a few that we came up with: 1 + 2 + 4/6 + 5 + 7/3 + 89 = 100
12 + 6/3 + 75 + 8/4 + 9 = 100
1/6 + 2 + 4/8 + 7/3 + 95 = 100
24 + 57 + 6/3 + 8 + 9/1 = 100
36 + 4/8 + 51 + 7/2 + 9 = 100
3/2 + 5 + 6/8 + 7/4 + 91 = 100

Solution:

The receptionist was pretty clever she played with the mute button of the phone while talking with her mother. She muted everything except the word emergency, call and help. So while talking, she sounded like 'Emergency… Call… Help' to her mother and thus she called the police.

Solution:

In the corners of the square, tighten two ropes. Tighten another rope between them by putting rings on each rope. That rope should be tightened on the sheep's neck on the other end.

Solution:

There are three roses and four bees.

Solution:

It is best if the person sits on the back of the train. After the stop, the train will be accelerating as it goes into the tunnel. Thus the train will be much master when the back of the train enters the tunnel. In this way, he will have to spend much less time in the tunnel.

Solution:

The women is a of short stature. She can't reach the upper elevator buttons, but can push is with his umbrella.

Solution:

19

Explanation:
The children can purchase 19 chocolates in return.

Out of 77 wrappers, 75 will be used to buy 15 chocolates and two will be left spare.
The 15 chocolates will create 15 empty wrappers that can be exchanged to get three chocolates.
Three chocolates will return three wrappers which will help them buy another chocolate.
Now the wrapper from this chocolate and the two spare that were left earlier will get them another chocolate.
15 + 3 + 1 = 19

Solution:

Both will rotate at Same speed.

Explanation:
Gears of the same size will always rotate at constant speeds despite any smaller or larger gears in between them.

Solution:

The brain teaser can be solved as shown in the image below.

Solution:

One Minute building

building 62 => Sixty second building => One minute building

Solution:

Solution can be verified from the picture below.