A plane crashed between the border of Mexico and America. Where do you bury the survivors?

Why do we preferably have round manhole covers and not square ones?

What's the only room from which no one can enter or leave

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?

At my favorite fruit stand,
an orange costs 18,
a pineapple costs 27,
and a grape costs 15.
Using the same logic, can you tell how much a mango costs?

10+10 and 11+11 can give you the same answer.

Explain how?

What is the largest number you can write with just 3 digits?

If in a code language, DISTANCE is written as IDTUBECN and DOCUMENT is written as ODDVNTNE, the how will THURSDAY be coded as in the same language?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211