The expression given is similar to the formula for compound interest, so the word problem must involve something to do with exponential growth. This can be a population of animals, cells, birds etc.
The starting number is 500.
The rate of growth is
There are 20 intervals of time - whether this is days, weeks, months, years, will be your choice.
Note that it is an expression, not an equation, because it is not equal to a given value yet, and there is no unknown to solve for,
So you could start off with something like..
A population of 500 penguins increases at a rate of .....
How many will there be after .....
Hope this helps.
This is an equation of compounded growth. See explanation for one possible worded question.
What is the final sum in a savings account after 20 years if the principle sum is 500 and the compound interest is 1.75% calculated annually?
So the equation would look like this: