Question

Which option is the best. Use math to support ur answer.

Option A: A 2 liter botyle of pop cost $1.29

Opyion B: A sxi pack of 1/2 liter bottles cost $2.99
Option C: A 12 pack of 0.35 liter cans cost $3.50

Answer 1

The option A has the cheapest price of the liter, so it is the better buy.

Explanation:

The best buy is going to be the one with the lowest liter price.

The liter price of each option can be found by a rule of three problem:

Rule of three problem:

In a rule of three problem, the first step is identifying the measures and how they are related, if their relationship is direct of inverse.

When the relationship between the measures is direct, as the value of one measure increases, the value of the other measure is going to increase too. In this case, the rule of three is a cross multiplication.

When the relationship between the measures is inverse, as the value of one measure increases, the value of the other measure will decrease. In this case, the rule of three is a line multiplication.

For each option, in this problem, the measures are:

- The number of liters bought

- The total cost

As the number of liters bought increases, so will the total cost. It means that the relationship between the measures is direct.

Option A:

2 liters - $1.29

1 liter - x

2x = 1.29

`x = (1.29)/(2)`

x = 0.645

In option A, each liter costs $0.645

Option B

A six pack of half a liter was bought. So in all, 3 liters were bought.

3 liters - $2.99

1 liter - x

3x = 2.99

`x = (2.99)/(3)`

x = $0.997

In option B, each liter costs $0.997

Option C

A 12 pack of half a 0.35 liter was bought. So in all, 4.2 liters were bought

4.2 liters - $3.50

1 liter - x

4.2x = 3.50

`x = (3.5)/(4.2)`

x = $0.8333

In option C, each liter costs $0.8333

The option A has the cheapest price of the liter, so it is the better buy.