in the process of identifying the alcohol contained in the wine, why does color changed into light blue from brown, to dark green, to light green and finally to light blue?

The color of the Anthocyanins changes depending on the PH of what they come into contact with, because wine already has acid in its Anthocyanins are red. But as soon as you expose those Anthocyanins to more alkaline factors, it will start to turn blue.

the assestment will probley apele with cause and effect

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