The amount of decrease is (80 - 64) = 16
The fraction of decrease is the fraction of the original amount that disappeared.
That fraction is (16 / 80) = 1/5 = 0.2
To change a decimal to a percent,
move the decimal point 2 places that way ==> .
0.2 = 20%
$30, because basically, it's -100, +100, -30.
You would have to divide 25 by 4. You would get 6.25. That means that Melinda can babysit for 6 hours.

it is true; just work them out, you should get what they got :))
144 cm3 is what i came up with!