Michael is saving for new iPhone. He gets £30 as pocket money per week, however he spends 20% of the whole amount for leisure and his savings only consists of the residue amount. If an iPhone costs £600 how many weeks would Michael need to save for it?

Given: £30 pounds per week 20% = 0.2 = 1/5 - spending on leisure

To find: a) Residue amount (Ra) b) How many weeks does Michael need to save (Tw)

Solution: a) To the find residue amount we must remove the leisure one first.

(pocket money) x (percentage spent on leisure) = money spent on leisure 30x0.2 = 6

Ra = (pocket money) - {(pocket money) x (percentage spent on leisure)}

Ra = 30-6 --> £24 pounds per week

b) In order to find how many weeks would Michael need to save for an iPhone we simply need to devide the cost of the iPhone by Ra. As Ra is measured in weeks no conversion is required.

Tw = (cost of the phone)/Ra Tw = 600/24 = 25 weeks

Answers: a) Ra = £24 b) Tw = 25 weeks