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

What am I?

Dwayne Johnson was running away with the loot from a heist in his car along with Vin Diesel. One tire was punctured and he dropped down to replace it. While changing the wheel, he dropped the four nuts that were holding the wheel and they fell into a drain. Vin Diesel gave him an idea using which they were able to drive till the rendezvous point.

What was the idea ?

A lily pad doubles in size every day. If on the 60th day, the pond is exactly filled with the lily pad, on what day is the pond exactly half covered?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

Can you identify the hidden rebus in the image below?

People make me, save me, change me, raise me. What am I?

John is found dead in his office at his desk. The police have narrowed the suspects down to three people: Mrs. Jacob, John’s wife Hena and his business partner Jason . All three visited John on the day of his murder, but all three provide the police with stories of explanation as to the reason for their visit.
Police found John with his wrist watch still on his right arm, a torn up picture of his wife laying on the floor beside the trash can, and an ink pen in his right hand. On the desk, the police found a name plate, a telephone that was off the hook, and a personal calendar turned to the July 5th page with 7B91011 written on it. After examining this evidence, the police knew their suspect. Who was it ?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Yesterday I fell from 30 feet high ladder but I don't get hurt. Why?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?