We then repeat this for 100, 200, 300, up to 900 – which is 200 9's.
But from 900 to 999 we have an extra 100 9's as each starts with a 9.
So the total is 300.
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Puzzle 199
Many years ago, a cruise liner sank in the middle of the Atlantic Ocean. The castaways luckily landed on a remote desert island.
There was enough food for the 135 people to last four weeks.
Nine days later a rescue ship appeared, unluckily this ship also sank, leaving an additional 36 people stranded on the island to now share the original rationed food.
The food obviously had to be re-rationed, everyone was now on three-quarters of the original ration, so how many days in total would the food last, from the day of the original sinking?
Originally there was enough food for 135 people for 28 days, which totals 3780 rations.
After 9 days, 1215 rations had been eaten.
Therefore there were now 2565 rations left for 171 people, which would last for another 20 days at three-quarter rations per person = (2565 ÷ 3/4) / 171.
Which is 29 days in total from the original sinking.
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Puzzle 200
Last week I spent half of my money on a new jacket, and then I spent half of that amount on some new trousers.
