Respuesta :

(1/2) / (1/4) = 1 / x......1/2 wall to 1/4 hr = 1 whole wall to x hrs
cross multiply
(1/2)(x) = (1/4)(1)
1/2x = 1/4
x = 1/4 * 2
x = 2/4 reduces to 1/2....so it will take 1/2 hr (or 30 minutes) to paint the whole wall.
1/2 wall - 1/4 hour (15 minutes)

1 wall - 1/2 hour (30 minutes)