The tiny homes will be steel framed with timber floors, have rainwater tanks and compostable toilets.
Each home will have insulated panels and be self-supporting, allowing for easy construction.
Final answer is 14, when looking at with a larger picture:
http://www.independent.co.uk/extras/puzzles-and-games/facebook-fruit-puzzle-how-smart-are-you-try-these-brain-teasers-a6889576.html
" But it’s not as easy as it looks, looking closely at the puzzle we can see that there is only one...