A double-glazing salesman is paid 10% commission on every sale he makes.
In addition he is paid a £50 bonus if the sale is over £500.
a) If a customer buys £499 worth of windows from the salesman, what is his commission?
b) How much extra will he earn if he persuades the customer in a) to spend an extra £20?
a) If the customer buys £499 worth of windows, the salesman will earn a commission of 10% on that amount.
Commission = £499 * 0.1 = £49.90
b) If the customer spends an extra £20, the total purchase amount will be £499 + £20 = £519.
Since this amount is over £500, the salesman will also earn a £50 bonus.
Commission = 10% * £519 = £51.90
Therefore, the additional amount the salesman will earn is £51.90 - £49.90 = £2.