40% of 65
0.40(65) = 26 returned the survey. (assuming that everybody who took the survey returned it.)
(3) 62.5% cuz u take the total number of the students and u divide it by the number of students between 60 to 65
Let x gallons be the amount of pure antifreeze that should be added to the 30% solution to produce a solution that is 65% antifreeze. Then the total amount of antifreeze solution will be x+3 gallons.
There are 30% of pure antifreeze in 3 gallons of solution, then
3 gallons - 100%,
a gallons - 30%,
where a gallons is the amount of pure antifreeze in given solution.
Mathematically,

Now in new solution there will be x+0.9 gallons of pure antefreeze.
x+3 gallons - 100%,
x+0.9 - 65%
or

Answer: he should add 3 gallons of pure antifreeze.
30 percentage decrease, if you need me to explain I’ll be glad to help
D. X = 10
6x-20= 40
6x=40+20
6x=60
X=10