the hoover dam in the u. s produces 2 x 10 ^9 watts of electricity and is composed of 7 x 10^9 kg of concrete. concrete requires 1mj of energy to produce 1 kg
1) how much energy did it take to produce the dam?
2) how long is the "energy payback time" for the dam?
show your work.

1)

2) days

Step-by-step explanation:

1) First of all we use so the total energy will be .

2)Then we use and or

yes

step-by-step explanation:

yes

whole numbers.

step-by-step explanation:

we are given the average monthly rainfall (in millimeters) model r(m) for the years 1900-2009 as a function of the month number m.

as we can see m is taken for the number of months for years 1900-2009.

we know that number of months can't be a negative number or decimal number or a fraction.

so, the number of months could be only positive whole numbers.

therefore, whole numbers is more appropriate for the domain of r.