wai ling averaged 84 on her first three exams and 82 on her next 2 exams.what grade must she obtain on her sixth test in order to average 85 for all six exams?
94
In sunlight, a vertical stick 6 ft tall casts a shadow 2 ft long. At the same time a nearby tree casts a shadow 14 ft long. How tall is the tree? Round to the nearest tenth
To find out what grade Wai Ling must obtain on her sixth test in order to average 85 for all six exams, we can calculate the total combined scores she needs to achieve.
Wai Ling scored an average of 84 on her first three exams, so her combined score for those exams is 84 x 3 = 252.
She then scored an average of 82 on her next two exams, so her combined score for those exams is 82 x 2 = 164.
To have an average of 85 on all six exams, Wai Ling needs a total combined score of 85 x 6 = 510.
To find out the score she needs on her sixth test, subtract the total combined scores she already has from the desired total combined score:
510 - (252 + 164) = 94.
Therefore, Wai Ling must obtain a grade of 94 on her sixth test in order to average 85 for all six exams.
To find out the grade Wai Ling must obtain on her sixth test in order to average 85 for all six exams, we can use the formula for average, which is the sum of all the scores divided by the number of scores.
Let's break down the information we have:
Wai Ling's average on the first three exams = 84
Wai Ling's average on the next two exams = 82
To find the average of all six exams as 85, we can set up the equation:
(84 + 82 + x + x + x + x) / 6 = 85
Simplifying the equation, we get:
(84 + 82 + 4x) / 6 = 85
Combining like terms, we have:
(166 + 4x) / 6 = 85
Now, we can proceed to solve for x:
166 + 4x = 510
Subtracting 166 from both sides, we have:
4x = 344
Dividing both sides by 4, we find:
x = 86
Therefore, Wai Ling must obtain a grade of 86 on her sixth test in order to average 85 for all six exams.