Question

The cost of tea varies directly with the mass. Liz bought 4.5kg of tea for $10.35. What is the cost of 12kg of tea?

Answer 1

$27.6

Explanation:

10.35 divided by 4.5 = 2.3

$2.3 for 1 kg

2.3 times 12= 27.6

Answer 2

$ 27.6.

Explanation:

Let the cost of tea be C.

Let the mass of tea be M

From the question given, we were told that the cost of tea varies directly with the mass. This can be expressed as:

C & M

C = KM

K is called constant of proportionality.

C is the cost of the tea.

M is the mass of tea.

Next, we shall determine the constant of proportionality, K.

Cost (C) = $ 10.35

Mass (M) = 4.5 kg

Constant (K) =..?

C = KM

10.35 = K × 4.5

Divide both side by 4.5

K = 10.35/4.5

K = 2.3

Finally, we shall determine the cost of 12kg of tea as follow:

Mass (M) = 12 kg

Constant (K) = 2.3

Cost (C) =..?

C = KM

C = 2.3 × 12

C = $ 27.6

Therefore, the cost of 12 Kg of tea is $ 27.6