Question

The table below shows the cost of downloading songs from a website. Number of Songs Number of Songs Total Cost Total Cost 6 6 $ 1.80 $1.80 12 12 $ 3.60 $3.60 20 20 $ 6 $6 What is the constant of proportionality between the total cost and the number of songs?

Answer 1

Explanation:

To find the constant of proportionality, we can use the formula for a proportional relationship: y = kx, where y is the total cost, x is the number of songs, and k is the constant of proportionality.

Using the table, we can find two pairs of values for y and x:

When x = 6, y = $1.80

When x = 12, y = $3.60

We can set up a proportion:

y1 / x1 = y2 / x2

$1.80 / 6 = $3.60 / 12

Simplifying, we get:

$0.30 = $0.30

This tells us that the constant of proportionality is $0.30.

We can check this by using another pair of values:

When x = 20, y = $6

Using the formula y = kx, we get:

$6 = ($0.30)(20)

Simplifying, we get:

$6 = $6

This checks out, so we can be confident that the constant of proportionality is $0.30.