Answer:
She painted at a rate of: [tex]112.5\,\frac{ft^2}{h}[/tex]
Step-by-step explanation:
Notice that since Vida painted 3 rooms in the given time (12 hours), and each room had 450 square feet of painted wall, she painted a total of:
3 * 450 square feet = 1350 square feet = 1350 [tex]ft^2[/tex]
Since she painted that number of square feet in 12 hours, the rate at which she painted was:
[tex]rate=\,\frac{number\,of\,ft^2}{time} = \frac{1350\,ft^2}{12\,h} =112.5\, \frac{ft^2}{h}[/tex]
