Nikki and Dave both work as cleaners. The equation shown models the total amount,
�
n, in dollars that Nikki charges to clean carpets in
�
r rooms.

​
�
=
20
�
n=20r

The table shows the total amount,
�
d, in dollars that Dave charges to clean windows in
�
r rooms. He charges the same amount per room to clean windows.

Complete the table to show the amount that each person charges to clean
�
r rooms.

Number of rooms
(
�
)
(r) ​ Nikki's Charges​
(
�
)
(n) Dave's Charges​
(
�
)
(d)
​1 ​
​
12.50
12.50
​2 ​
​

​3 ​
​

​4 ​
​
50
50