Question

For every 3 lemons Chrissy buys at a farm stand,

the total cost increases by $1.80.
The constant of proportionality is ?
An equation that relates the total cost, y, and the
number of lemons, x, is y = ? x.
Use the equation you wrote to complete the table.


Table:

Numbers of lemons(x) | Total cost(y)
4 | _?__
_?__ | $4.20
_?__ | $9.00
18 | _?__

Answer 1

The constant of proportionality is $1.80

y = 1.80x

Explanation:

The constant of proportionality is $1.80

An equation that relates the total cost, y, and the number of lemons, x, is

y = 1.80x

where,

y =Total cost

x = number of lemon

When x = 4

y = 1.80x

y = 1.80(4)

y = 7.2

y = $7.2

When y = $4.20

y = 1.80x

4.20 = 1.80x

x = 4.20 / 1.80

x = 2 1/3

x = 2 1/3

When y = $9.00

y = 1.80x

9.00 = 1.80x

x = 9.00 / 1.80

x = 5

x = 5

When x = 18

y = 1.80x

y = 1.80 × 18

y = 32.4

y = $32.4