If you were trying to describe the difference between power and work you could say: to find power we need to know force and velocity; to find work we need to know force and distance. to find power we need to know energy and distance; to find work we need to know energy and time. to find power we need to know distance and time; to find work we need to know velocity and distance. to find power we need to know energy and velocity; to find work we need to know distance and force.

When trying to describe the difference between power and work, I could say to find power we need to know force and velocity; to find work we need to know force and distance.  

Option A  

Explanation:

Power is best defined through force and velocity whereas work is best defined through force and distance in the parallel direction.

Let’s understand the difference through the respective formulae.

Power is defined as the work done (W) in a unit time (t), i.e.

And work (W) is defined as a force applied to move the object to a particular distance, i.e.

If we apply the formula of Work in the equation of Power, we see;

Where,

So, here what we can easily understand that to evaluate power, we need to know force and velocity and to find work we need to know force and distance.

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