posted by lily .
each week, mandy's algebra teacher gives a 10 point math quiz. after 5 weeks, mandy has earned a total of 36 points for an average of 7.2 points per quiz. she would like to raise her average to 9 points. on how many quizzes must she score 10 points in order to reach her goal?
guess and check is the best way!
total is 5 quizzes and she has 36 points so 7.2*5 (weeks) = 36 and add 10 to 36, 14 times so just add 140 and you get 176/19(#number of weeks 14+5) and you get 9.2 as the average. hope this is what you were looking for. sorry if its not