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An athlete must each day run three laps more than the day before. On the sixth day she runs 17laps

Calculate how many laps she runs 1.) on the first day 2.) in total by the end of the sixth day.

in 1.

I know that Un=U1+(n-1)d

where d=3

Un=17

n=6

i then get 17= U1 + (6-1)3, and I get U = 2

In 2 i use S=(n/2)(2*U1 + (n-1)d)

so S = (6/2)(2*2+(6-1)3) =57 (in the answer sheet it says that it's 42) what am I doing wrong?