If Sally walked 1⁄2 kilometer in 1⁄4 hour, how fast, in kilometers per hour, was she walking?

Kilometers per 1 hour

1/4 times what=1?

times both sides by 4/1

what=4

(1/2km) / (1/4hr) times 4/4 = (4/2km) / (4/4hr) = 2km/1hr=2kmph

another way

(1/2) / (1/4) = (1/2) (4/1) = (4/2) = 2kmph

We need to get it per hour, so multiply everything by 4 since right now we're at a quarter of an hour, so you get 2km/hr.