What is 10% of 2,000 ? 200.
so 2,000+200 = 2,200 for the 1st year
What is 10% of 2,200 ? 220.
2,200+220 = 2420 for the 2nd year
What is 10% of 2,420 ? 242.
2420 + 242 = 2662 for the 3rd year
What is 10% of 2662 ? 266.2
2662 + 266.2 = 2928.2
So that's how much they spent each year, now to get the total we add them together.
2928.2 + 2,662. + 2,420. + 2,200. = 10,210.2