Solution:

21

Solution:

It is because there is not a single (unmarried) person it.

Solution:

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

Solution:

It is a towel.

Solution:

The correct way to solve this question is go backwards. If the number of marble gets doubled every minute and after two hours, it is filled completely, one minute ago it would be half.

So, it will take 1 hour and 59 minutes for it to be filled half.

Solution:

I am a tree.

Solution:

To be or not to be

Solution:

Joey sold 15 ice creams that day.

The fourth kid bought a single ice cream. Therefore, we have the following equation:
Total - (Total / 2 + 1/2) = 1
Solving it, we get the total as 3.

Let's work this method till we reach the first kid.

The first kid bought 15 / 2 + 1/2 = 8 (leaving 7)
The second kid bought 7 / 2 + 1/2 = 4 (leaving 3)
The third kid bought 3 / 2 + 1/2 = 2 (leaving 1)
The fourth kid bought 1 / 2 + 1/2 = 1

Adding all of them together, we get
8 + 4 + 2 + 1 = 15.

Solution:

80

Explanation:
21 B 7 C 9 D 10 A 13
= 21 / 7 + 9 X 10 - 13
= 3 + 90 - 13
= 80

Solution:

The total number of students is 500.

To follow how and why, please see the venn diagram.