Random Puzzles 

Workings

Hint
Do leap years make a difference?

Answer
Hours in 10 years.

Reasoning
In a day, there are 60 x 60 x 24 seconds = 86,400 seconds.

In 10 years, there are 10 x 365 x 24 hours = 87,600 hours, which even without the leap years is already the larger number.

Workings

Hint
There are no larger squares than size 4 x 4.

Answer
There are 110 squares without a rook.

Reasoning
There are 60 squares of size 1 x 1.
There are 35 squares of size 2 x 2.
There are 12 squares of size 3 x 3.
There are  3 squares of size 4 x 4.

Giving a total of 60 + 35 + 12 + 3 = 110 squares.

Workings

Hint
You might need an old calculator.

Answer
Coil.

Reasoning
This is the only word that cannot be spelled using a calculator.

For example, if you enter 376616 into an old-fashioned calculator, and look at the number upside down, you can read GIGGLE.
376616  = giggle
7105    = soil
57738   = bells
378806  = gobble
4506    = gosh
5508    = boss
3704    = hole
5355378 = blesses
coil    = ????

Workings

Hint
The list is related to numbers.

Answer
Llama.

The length of each word is the same length as the numbers one, two, three, four, five, six, etc.

The next number is SEVEN, which has 5 letters, and llama is the only word with 5 letters.