After taking 5 quizzes your average is 72 out of 100. What must your average score be on the next five quizzes to increase your average to 78?
2006-06-29 23:45:28 · 7 answers · asked by Math Geek 1 in Science & Mathematics ➔ Mathematics
This can be simplified. It doesn't matter if it's five quizzes or a hundred quizzes, or just one. It's two sets of quizzes, equal size.
So, just take the difference and add it in the opposite direction.
78 - 72 = 6
78 + 6 = 84
You need to average 84.
Note this method would NOT work if you had 4 quizzes and needed to figure out what you have to get on the next 7.
2006-06-29 23:55:16 · answer #1 · answered by I Know Nuttin 5 · 0⤊ 0⤋
To have an average of 78 on 10 quizzes you need a total of 780 points.
After 5, you have 360 points.
You need 420 on the next 5.
Average is 84.
2006-06-29 23:51:30 · answer #2 · answered by Bill S 6 · 0⤊ 0⤋
84
2006-06-30 00:34:46 · answer #3 · answered by Anonymous · 0⤊ 0⤋
84
2006-06-29 23:51:34 · answer #4 · answered by R S 4 · 0⤊ 0⤋
84
2006-06-29 23:48:51 · answer #5 · answered by Ivanhoe Fats 6 · 0⤊ 0⤋
Same as the previous question asked by u
2006-06-29 23:49:48 · answer #6 · answered by payal_kothari_acclaris 2 · 0⤊ 0⤋
81%
75 + x
-------- = 78
2
hence x = 78*2 +75
x = 81.
^^
2006-06-29 23:49:46 · answer #7 · answered by ? 5 · 0⤊ 0⤋