Answer: U' = (0, 1)
<u>Step-by-step explanation:</u>
U = (3, -5)
rotate 90° counterclockwise means (x, y) = (-y, x)
new U = (5, 3)
down 2 units means subtract 2 from the y-coordinate
newer U = (5, 1)
left 5 units means subtract 5 from the x-coordinate
U' = (0, 1)
16 / 12 = 1.3333
Answer: she mowed 1 1/3 lawns per hour.