Random Puzzles 

Workings

Hint
A very common sequence, but in base 8!

Answer
13.

Odd numbers expressed in base 8, 11 in base 8 = 13.

Workings

Hint
Adding just one should be enough.

Answer
Holes!

Workings

Hint
Try starting with the water.

Answer
This puzzle is a classic one that has no solution in 2D.

However, if you place the items on a doughnut shape in 3D you can solve it.

In the picture below, the electricity is linked to House 3 by going over the top and re-entering through the hole in the middle.

Workings

Hint
This is a tricky question related to number bases.

Answer
200.

Each number in the sequence is a representation of the number 32 in different bases, starting with base 10.
Base 10: 32  = 3 x 10^1 + 2 x 10^0          = 3 x 10 + 2         = 32
Base 9 : 35  = 3 x 9^1  + 5 x 9^0           = 3 x 9 + 5          = 32
Base 8 : 40  = 4 x 8^1  + 0 x 8^0           = 4 x 8 + 0          = 32
Base 7 : 44  = 4 x 7^1  + 4 x 7^0           = 4 x 7 + 4          = 32
Base 6 : 52  = 5 x 6^1  + 2 x 6^0           = 5 x 6 + 2          = 32
Base 5 : 112 = 1 x 5^2  + 1 x 5^1 + 2 x 5^0 = 1 x 25 + 1 x 5 + 2 = 32
Base 4 : 200 = 2 x 4^2  + 0 x 4^1 + 0 x 4^0 = 2 x 16 + 0 + 0     = 32