What has one letter and starts with an E?

On a certain day, John celebrated his birthday. Two days later, his older twin brother Jacob celebrated his birthday.

Is this even possible? How can it be?

What has 13 hearts but no other organs?

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

Explain how?

The following "Brain Bat" means Slow Down.
S
L
O
W

Using the same logic, can you tell us what does the following Brain Bat means ?
E
V
I
G

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

You are given 2 eggs.
You have access to a 100-storey building.
Eggs can be very hard or very fragile means it may break if dropped from the first floor or may not even break if dropped from 100th floor, Both eggs are identical.
You need to figure out the highest floor of a 100-storey building an egg can be dropped without breaking.
Now the question is how many drops you need to make. You are allowed to break 2 eggs in the process

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

what's the probability of getting a king or a queen from a pack of 52 cards?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?