### Burning Down

One night two candles were lit. Can you work out how long each candle was originally?

### Percentage Unchanged

If the base of a rectangle is increased by 10% and the area is unchanged, by what percentage is the width decreased by ?

### Digit Sum

What is the sum of all the digits in all the integers from one to one million?

# Rough Root

##### Age 14 to 16 ShortChallenge Level

Which of these is closest to $\sqrt{\dfrac{10 000}{2012}}$?

a) 1.9
b) 2.2
c) 2.5
d) 2.7

This problem is taken from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.