At noon, a tank contained 8 cm of water. after several hours, it contained 4 cm of water. what is the percent decrease of water in the tank?

50%

Step-by-step explanation:

The water decreased by 50% because the water started at 8 cm and went down to 4 cm. Half of 8 is 4, or if you multiply 8 by .5, or 50%, you get 4.

in the attachment.   i didn't see your choices.   the word which means there is choices.

step-by-step explanation:

(x,y)

x tells you how much left or right you go from the origin

y tells you how much down or up you go from the origin

so for example (-3,2), you go left 3 and up twice. i denoted which of the ordered pairs is which in my graph.