Mervin tells Aquilla that he has a bag with very small rocks in it.

She asks how many, and he says that if you add one hundred million
very small rocks to the bag, it will contain 36 more very small rocks
than the number in ten thousand of the bags minus five times the
number in the bag. How many very small rocks are in Mervin’s bag?

Let n = number of rocks in bag. The clues suggest:

n + 100,000,000 = 36 + 10,000n - 5n.
Solving for n gives: n = 10,006 rocks.
Those rocks must be pretty small, or the bag pretty big!