Common ratio means the multiplier applied to a previous year to get the next year's value. For example, production was 1000 units this year, the common ratio is 1.62, so next year production is 1.62*1000=1620, with an increase of 620 units over preceding year of 1000. So the percentage change is 620/1000 = 0.62 = 62%.
To answer this question, you need to makes the unit of the smartphone screen same. In this case, phone A is using decimal and phone B is using a fraction. You can use which was easier.
Let's try to use decimal. Then you need to convert phone B fraction width into decimal width. The calculation would be: 5cm + 1/3cm= 5 cm + 0.333cm= 5.333cm
From here it clear that phone B has a wider screen than phone A.
