Find the work done by a 75.0 kg person in climbing a 2.50 m flight of stairs at a constant speed.

1,839.375 Joules

Explanation:

Work is said to be done is the force applied to an object cause the object to move through a distance.

Workdone = Force * Distance

Workdone = mass * acceleration due to gravity * distance

Given

Mass = 75.0kg

acceleration due to gravity = 9.81m/s²

distance = 2.50m

Substitute the given parameters into the formula:

Workdone = 75.0*9.81*2.50

Workdone = 1,839.375Joules

Hence the workdone is 1,839.375 Joules

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