First, Katie blew up a red one. After her first puff her balloon had a circumference of 24 cm.
Her second puff added 12 as much again to that.
Her third puff increased it by 13.
Her fourth puff increased it by 14 and her fifth puff by 15.
Her sixth puff increased it by 16 and at the beginning of her seventh puff it went
Next, Will blew up a blue balloon. After his first puff his balloon had a circumference of 14 cm.
And, just like Katie's, his second puff added 12 as much again to that and his third puff increased it by 13.
His fourth puff increased it by 14 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?