Painting the wall

Question

Brandi will paint (1/10) of her wall on day 1, then paint (1/10) of the unpainted wall on day 2, etc. Write an expression of the portion of the wall Brandi has painted after n days.

Answer 1

If Brandi paints at the rate every day

day 1, 1/10

day 2, 1/10, total 2/10

day 3, 1/10, total 3/10

day 4, 1/10, total 4/10

day n, 1/10, total n/10