Alex mows a lawn that measures 800 square feet in 2 1/2 hours. At this rate, how many square feet of lawn can Alex mow in 1 hour?

320 square feet per hour

Step-by-step explanation:

800/2.5=320

the perimeter is increased by a factor of 2

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!