500 elves currently live in the great elf kingdom. the elves are very prolific, with a birth rate of 20% per year. the elves also live for a long time, so the death rate per year is only 5% of the population. in addition, 55 new elves per year are coming into the kingdom due to a volcanic eruption in the not-so-great elf kingdom. use a mass balance to determine the accumulation rate.

The yearly accumulation for the current year is 130

Explanation:

Accumulation is defined as

input - output = accumulation

The accumulation rate is accumulation per unit of time (in this case a year)

The accumulation rate will then be the amount of births, plus the amount of immigrants minus the amount of deaths.

ar = 500*0.2 + 55 - 0.05*500

ar = 100 + 55 - 25

ar = 130

hello there!

your answer is a “generator”

a generator does not create energy but instead it transforms it.

it’s basically a motor working in reverse.

d is the correct answer