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

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

The two towns are exactly 100 km apart. John leaves City A driving at 30 km/hr and Jacob leaves City B half an hour later driving at 60 km/hr. Who will be closer to City A when they meet?

A number with an interesting property:

When I divide it by 2, the remainder is 1.
When I divide it by 3, the remainder is 2.
When I divide it by 4, the remainder is 3.
When I divide it by 5, the remainder is 4.
When I divide it by 6, the remainder is 5.
When I divide it by 7, the remainder is 6.
When I divide it by 8, the remainder is 7.
When I divide it by 9, the remainder is 8.
When I divide it by 10, the remainder is 9.

It's not a small number, but it's not really big, either.
When I looked for a smaller number with this property I couldn't find one.

Can you find it?

Which number should replace the question mark?

An office is divided into 8 cubicles. How many of the cubicles are painted if only 1/8 of the cubicles are painted?

What runs around the whole yard without moving?

You can see three almost identical images below. Can you spot the odd one out from them?

The dirtier I get, the whiter I look. Who am I?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?