Today’s puzzle has been doing the rounds on social media. Your challenge is to find the height of the red bar.
Scroll down for a clue and further down for the answer.
*
*
*
*
*
*
*
Clue: If the 4m high shadow on the wall was a real object, it would produce a 6m horizontal shadow. This is based on the ratio of the green block’s height to shadow.
Scroll down for the answer.
*
*
*
*
*
*
*
Answer: The red bar has a height of 8 metres.
We can see that the 2m high green block produces a shadow of 3m. From this, we can deduce that if the 4m shadow on the wall was a real object, it would produce a horizontal shadow of 6m. This means, if the wall wasn’t in the way, the red block would produce a 12m shadow (6m + 6m). As the shadows are always two-thirds the height of the block, this means the red block’s height is two-thirds of 12m, which is 8m.
Puzzle a Day 