Solution:

sawdust

Solution:

The guard and the prisoner cross the river
The guard comes back
The guard and the girl cross the river.
The guard and the prisoner comes back.
The mother and the girl cross the river.
Mother comes back
The mother and the father cross the river
Father comes back
The guard and the prisoner cross the river
Mother comes back
The father and the mother cross the river
Father comes back
The father and the boy cross the river
The guard and the prisoner comes back
The guard and the boy cross the river
The guard comes back
The guard and the prisoner cross the river.

Solution:

The original price is $83.33.
(20 percent of the taxes are added to the selling price.)

Solution:

The question tells us that a taxi driver was going the wrong way. It is however not mentioned that he was driving the cab. As per the question, it is evident that he was on foot and that is why the police officer did not fine him.

Solution:

He cannot marry his widow's sister in any country. This is because if his wife is a widow, he is already dead.

Solution:

6/(1 - 3/4) = 24

Solution:

276

Explanation:
6 = 1^1 + 2^1 + 3^1
14 = 1^2 + 2^2 + 3^2
36 = 1^3 + 2^3 + 3^3
98 = 1^4 + 2^4 + 3^4

Thus the next number will be
1^5 + 2^5 + 3^5 = 276

Solution:

I am grape.

Solution:

The missing number is 11.

Explanation:
The patter here is that the number on the right is half of the product of the other two numbers.

(18*4)/2 = 36
(15*6)/2 = 45

In the same manner,
(8*x)/2 = 44
=> x = 11

Solution:

Give Up

SLOW when read down gives us Slow Down.
GIVE when read upwards gives us Give Up.