Brain Teasers and Puzzles 

Workings

Hint
A very tricky puzzle involving prime numbers.

Answer
101.

These are prime numbers, which, when reversed, are also prime.

Workings

Hint
How much soil is in any hole?

Answer
None!

Workings

Hint
It will take a while to check 1 x 7, 2 x 7, 3 x 7. What do we know about the answer?

Answer
63,492 x 7 = 444,444

Reasoning
We can work backwards, as we know that the number multiplied by 7 has only 4's. We can try the following:
      4 ÷ 7 ≈ 0.57     x
     44 ÷ 7 ≈ 6.29     x
    444 ÷ 7 ≈ 63.43    x
  4,444 ÷ 7 ≈ 634.86   x
 44,444 ÷ 7 ≈ 6,349.14 x
444,444 ÷ 7 = 63,492

Workings

Hint
The final word starts with AI.

Answer
Isle becomes aisle.