Alex wants to buy a new phone. It costs £280. Alex’s weekly wage is £420. He saves 15% of his wage each week. How many weeks does it take Alex to save enough money to buy the phone?

Total wage each week= £420. In one week, he saves 15% of this: 15% of 420 is 0.15 x 420 = £63. So he saves £63 in one week. To calculate the total number of weeks it takes to save up for the phone, divide 280 by 63:280÷63=4.444... weeks, which is 4 and 4/9 ths of a week. 4/9ths of a week is (4/9)x7 days. This is equal to 3.1 days, but since he is only paid weekly and not daily, he will take 5 weeks to save up for the phone.