Answer:
2 50ml bottles
Step-by-step explanation:
Reading through the question, we have:
For 80mL
[tex]C_1 = \pounds 55[/tex]
For 2 50mL bottles.
The cost is calculated by the original cost + half the original cost.
i.e.
[tex]C_2 = \pounds 45 + \frac{1}{2} * \pounds 45[/tex]
[tex]C_2 = \pounds 45 + \pounds 22.5[/tex]
[tex]C_2 = \pounds 67.5[/tex]
Next, is to calculate the unit price of each.
For 80mL
[tex]C_1 = \pounds 55[/tex]
[tex]Unit\ price = 55/80[/tex]
[tex]Unit\ price = 0.6875[/tex]
For 2 50mL bottles.
[tex]C_2 = \pounds 67.5[/tex]
[tex]Unit\ price - 67.5/(2 * 50)[/tex]
[tex]Unit\ price = 67.5/100[/tex]
[tex]Unit\ price = 0.675[/tex]
By comparison, the 2 50mL is the best buy because it has smaller unit price
