The price of a particular share varies from day to day. On Monday the price of the share was £1. Tuesday’s price was 20% higher than Monday’s, and Thursday’s price was 25% up on Wednesday’s price. By the Friday of that week the price had returned to £1. Helen bought £1000 worth of this share on Monday and then sold them on Thursday to make a profit of £350. Paul bought £3000 worth of this share on Tuesday, but had to sell them the following day.