An office building has three air conditioning units, one for each office. each unit runs only when employees are working. the
tables below show the number of hours employees worked at each office over a three-month period and the total air
conditioning electric costs for the entire office for each month.
june
july
august
number of hours worked
unit a
unit b
184
207
174
198
168
189
unit c
276
264
242
total air conditioning electric costs
june
$142.60
july
$135.96
august
$128.30
how much does it cost to run unit a per hour?