Brain Teasers and Puzzles 

Workings

Hint
The first in the list would be Hydrogen.

Answer
Fluorine.

These are the elements in atomic number order.

Workings

Hint
What abilities do each of these birds have?

Answer
Ostrich.

Because it is the only one which cannot fly.

Workings

Hint
A fathom is 6 feet.

Answer
Hours in a month.

Reasoning
A fathom is 6 feet, which is 1.8288 metres.

So there are 1000 ÷ 1.8288 ≈ 546.8 fathoms in a kilometre.

The shortest month has 28 x 24 hours = 672.

So even the shortest month has more hours than there are fathoms in a kilometre.

Workings

Hint
Try finding the cube root of 190,747.

Answer
53, 59, and 61.

Reasoning
Start by taking the cube root of 190,747, which is approximately 57.56.

The next highest prime number is 59:

   190,747 ÷ 59 = 3,233

Let's try the next prime number, which is 61:

     3,233 ÷ 61 = 53

53, 59, and 61, are all prime, and are consecutive, so this is the answer.

Double-Checking
   53 x 59 x 61 = 190,747