Answer:
they paid a total of 590.49
Explanation:
1000 / 10 = 100 dollar discount he pays 900
900 / 10 = 90 they got a 90 dollar discount 810
810 / 10 = 81 they got an 81 dollar discount 729
729 / 10 = 72.9 they got a 72.9 dollar discount 656.1
656.1 / 10 = 65.61 they got a 65.61 dollar discount 590.49