Data:
1 litre = 1000 mL
If:
1000 mL → £3.50
200 mL → y
Solving: Rule of three (directly proportional)
[tex] \frac{1000}{200} = \frac{3.50}{y} [/tex]
Product of extremes equals product of means:
[tex]1000*y = 3.50*200[/tex]
[tex]1000y = 700[/tex]
[tex]y = \frac{700}{1000} [/tex]
[tex]y = 0.7\to \boxed{\boxed{y = \£0.70}}\end{array}}\qquad\quad\checkmark[/tex]
