How much horsepower is needed to lift a box that is 10 lb 3 ft in 10 seconds

Work to lift the box:

Work = (force) x (distance)

Work = (10 lb) x (3 ft)

Work = 30 ft-lbs

Power = (work done) / (time to do the work)

Power = (30 ft-lbs) / (10 seconds)

Power = 3 ft-lbs/second

1 Horsepower = 550 ft-lbs/second

(3 / 550) = 0.0055 Horsepower

yup its correct its: c) b b

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form