Every morning Sasha exercises for 20 minutes. She exercises k minutes every evening. Next week she will double her exercise time at night. Write an algebraic expression to show how long Sasha will exercise each day next week.
If k=20 minutes Each day Sasha will exercise 2 times more. 2 times more than k is 2k. So first week Sasha will exercise k+2k+3k+4k+5k+6k=20+40+60+80+100+120=440 minutes The formula to show how long Sasha will exercise each day next week is: 440 + 20*x where 440 is initial exercise time, and x is number of day in next week.
