Answer:
Dan has £54 left
Explanation:
Dan's weekly wages are £540.
Then his spending includes (2/5)w + (5/10()w, or (9/10)w, and this is subtracted from Dan's wages: £540 - (expenses)
£540 - (9/10)(£540) = £54
Dan has £54 left after having spent 9/10 of his weekly wages on rent and food.