What goes up but never comes down?

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

What four weights can be used to balance from 1 to 30 pounds?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

Can you tell a 3D object that has just two surfaces?

What is the next number in the series?

15 29 56 108 208 ?

Steffi's daughter Jazelle needs to be picked up from school every day.
Steffi asks one of her colleagues to pick up Jazelle from the school. Steffi devised a password system to confirm that Jazelle goes with the correct colleague only.

The password on Monday was SJM16.
The password on Wednesday was TAW39.

What will the password be for Friday?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?