Why 1729 is a magic number? Answer Logically.

If your uncle’s sister is not your aunt, what relation is she to you?

You can hear me, but you can't touch or see me.

What am I?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

What always comes into a house through the keyhole?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

Which statement is true out of the following?
One statement here is false.
Two statements here are false.
Three statements here are false.

What number comes next in this sequence:
7 8 5 5 3 4 4 _