Solution:

This one definitely sounds too unusual. But there is an easy way to look at things.

Let us say that there is one unfaithful husband in the town. In such a case, 99 women will know about him. The wife of that man will be the only one who will not know about him and would have always thought that his husband is truly faithful to her. But since the mayor announced that there is at least one cheater among them, she will come to a realization that her husband must be cheating on her. So her husband will be executed on the first day of the announcement.

Now let us take up a case that there are two cheating husbands in the town. Now 98 women of the town must be knowing about them both. The two wives of those men will think that there is only one cheater in the town. Both of them believes that their respective husbands are loyal and this would not report about them

But when both of them will find out on the next day that no one was executed, they will realize that it could only mean that both of their husbands are cheaters. Thus both the husbands will be executed on the second day.

Thus if we have X number of cheating husbands, they all will die on the Xth day after the announcement is being made.

Solution:

Steps:
1) Light fire on first bar from both the ends and second bar from one end.

2) After 30 seconds(when first bar gets completely burned out) , burn the second bar from second end as well.

3) When second run completely gets burned , you know its 45 seconds.

Solution:

The Lady sitting in the chair has the detector attached to the back of her blouse.

Solution:

First fill the 8 liters jug complete - 4, 8, 0
Fill the 5 liters jug with 8 liters jug - 4, 3, 5
Pour back the beer from 5 liters jug to 12 liters jug - 9, 3, 0
Pour the 3 liters from 8 liters jug to 5 liters jug - 9, 0, 3
Fill the 8 liters jug completely from 12 liters jug - 1, 8, 3
Fill the 5 liters jug from the 8 liters jug - 1, 6, 5
Pour the entire 5 liters jug back in 12 liters jug - 6, 6, 0

You have successfully split the beer into two equal parts.

Solution:

What must be kept in mind before you start calculating through any method is that the weights can be put on both the pans.

So the weights - 1, 3, 7, 12, 43, 76, 102

The oldest man that can be weighed using these weights is a man aged 122 years

Solution:

9

Explanation:
2 < 3 < 5
To find out the required number of candies, take one in place of the least number (i.e. take one mango candy) and then add all the greater numbers (i.e. three strawberry and five pineapple candies) to it.

Required number of balls = 1 + 3 + 5 = 9.

Solution:

Just One!

example
If u get Blue rock with label as "blue+red" => this is red as all labels are wrong.
In this way u can logically solve this puzzle.

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:

One of the cop will move clockwise while the other will move anti-clockwise every day. In such a manner, they will catch the thief in minimum seven days.

Solution:

36 meters.

100/v1 = 80/v2
100/v2 = 80/v3

20+(20/v2)*v3=20+16 = 36

Solution:

It can be down as shown below.