The first thing any good mathematician does is convert the measurements to the same unit as what the question is asking. In this problem, it states that the pool fills at a rate of 20 cubic meters per hour. Just keep in mind that an hour is 60 minutes.
The next step is to see how many cubic meters will cost $300. This can be done by dividing 300 by 10. This gets you 30 cubic meters of water.
You already know that 60 minutes is 20 cubic meters of water. That leaves the remaining 10 cubic meters of water. By dividing the rate given, you get that 30 minutes is 10 cubic meters of water. Add the 60 and 30 together to get 90 minutes.
It will take 90 minutes for the pump to use $300.
Answer:
ok?
Step-by-step explanation:
199.
the z score for the 90th percentile is 1.28, so you can solve the equation

which gets you the 199
X^2+16-38=0
find what 2 numbers multiply to get -38 and add to get 16
find factors of 38
2 times 19
there is no way to use common factor so use quadratic formula which is
x=

or x=

ax^2+bx+c=0 subsitte
a=1
b=16
c=-38
subsitute

=

=

=

=

so the answers for x are

and

which are aprox -2.099504938362 and +18.099504938362
so it would be
(x-[-8+√102])(x+[8+√102])=0