Weighted Averages

This is similar to figuring out your GPA

For each course…
Take the grade*weight = course total
Sum all course totals / Sum all weights = weighted average


Geometry
89 x 3 = 267
American Literature
92 x 3 = 276
American History
94 x 2 = 188
Biology
81 x 2 = 162
Sculpture
85 x 1 = 85


978 / 11 = 88.90909091 = 88.9 = C

This is similar to figuring out your GPA

For each course…
Take the grade*weight = course total
Sum all course totals / Sum all weights = weighted average


Geometry
89 x 3 = 267
American Literature
92 x 3 = 276
American History
94 x 2 = 188
Biology
81 x 2 = 162
Sculpture
85 x 1 = 85


978 / 11 = 88.90909091 = 88.9 = C

Travis_1234567890 wrote:This is similar to figuring out your GPA

For each course…
Take the grade*weight = course total
Sum all course totals / Sum all weights = weighted average


Geometry
89 x 3 = 267
American Literature
92 x 3 = 276
American History
94 x 2 = 188
Biology
81 x 2 = 162
Sculpture
85 x 1 = 85


978 / 11 = 88.90909091 = 88.9 = C

Great solution!

Here's the general weighted average formula:

Weighted Average = %weight group1*avg group1 + %weight group2*avg group2 + .....

In this case, the total number of units is 3+3+2+2+1 = 11.

So, math is 3/11 of total, english is 3/11, history is 2/11, science is 2/11 and art is 2/11. If we apply the formula to this question, we'd get:

Weighted Average = (3/11)89 + (3/11)92 + (2/11)94 + (2/11)81 + (1/11)85

Note that because of the ugly numbers in this question, the formula involves a lot of annoying calculations. In this instance, Travis's approach is much quicker. In fact, Travis actually applied the formula, he just did things in a slightly different order. Travis did it as:

(3*89 + 3*92 + 2*94 + 2*81 + 1*85)/11

which is the exact same calculation.

Thanks for the solution. I was dividing by 5 instead of 11.
Villanova did our GPAs automatically...LOL.