math
posted by terrell on .
Jane uses a jar to save her money. She saves $10 from her weekly allowance in the 1st week, $12 in the 2nd week, $14 in the 3rd week, and so on. How much money will she have saved in 10 weeks?

This is an AS with
a=10
d=2
So,
S10 = 10/2(2*10+9*2) = 190