In today's challenge, we will only be able to make a poster to show our working out.
Katie and Will have some balloons, some are red and some are blue.
Her second puff added as much again to that.
Her third puff increased it by .
Her fourth puff increased it by and her fifth puff by .
Her sixth puff increased it by and at the beginning of her seventh puff it went
And, just like Katie's, his second puff added as much again to that and his third puff increased it by .
His fourth puff increased it by and so on.
His balloon burst at exactly the same size as Katie's at the beginning of a puff.
How many puffs had Will done before his balloon burst?
- University of Cambridge