Find the next number in the sequence

5 12 24 36 ?

In a box, there is a jumble of 7 red balls, 6 blue balls, 5 green balls, and 4 yellow balls. What is the minimum number of balls, will you have to pick up so that you have at least 4 balls of the same colour?

Count the number of times the letter "F" appears in the following paragraph:

FAY FRIED FIFTY POUNDS OF
SALTED FISH AND THREE POUNDS
OF DRY FENNEL FOR DINNER FOR
FORTY MEMBERS OF HER FATHER'S FAMILY.

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

Two prisoners Jack and Jill are locked in a cell.
There is open window approx 40 feet above the ground of the cell.
They are never able to reach there.

Then they plan to escape by a tunnel and they start digging out.
After digging for more than 20 days, Jill comes with the different plan and they escaped.

what was the plan ?

If 2 workers can complete painting 2 walls in exactly 2 hours.

How many workers would be needed to paint 18 walls in 6 hours?

Two-person want to cross a river. Only one boat is present on the riverside that can carry only one person at a time.

However, they still manage to cross the river. How is it possible?

I know a nine-letter word having only one vowel.
Do you ?

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?