Fitness Fitness Fitness places an advertisement on their window stating:

The first 25 people to complete interval training on our brand new treadmill machines within five minutes, will be rewarded with one year's free membership.

Emily notices the advertisement and completes the task, within five minutes. Emily is one of the first 25 people. Whilst Emily is completing the interval training, the manager places a notice on the window withdrawing the promotion; the manager is refusing to give Emily her free membership for 12 months, stating that the promotion is no longer valid.

Advise Emily.