If you cut a apple and leave it in the open air and it turns brown what kind of chemical change is that

Oxidation

Explanation:

The browning of the apple after you cut it undergoes a natural chemical change called oxidation, wherein the apple's enzymes react with the oxygen in the environment.

force tends to be low and long diustance masses are high

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