Who knows how to average weight with grades?

[Cindy B]

I always get the calculation messed up.

Say if one section of a course is 40% of the grade
and three other sections were 20% how would you calculate the weight?

Here's the example 571/600 points available for the 40% part

And the three (each worth 20%) were 81/100, 82/100, and 82/100.

Ok, I cant formulize the 40% correctly.

I get an A everytime I calculate it, but I want to be doubly sure so I can ask for an account.

Who can calculate this correclty for me?

Thank

 

[jrydberg]

81 x .2 = 16.2
82 x .2 = 16.4
82 x .2 = 16.4

571/600 * 100= 95.167
95.167 x .4 = 38.067

16.2 + 16.4 + 16.4 + 38.067 = 87.067

 

[Cindy B]

Thanks.. I was taught another way to formulize it, and I kept on getting it incorrect.

87 ....rats!

 

[jrydberg]

You're welcome.

Sorry, I couldn't turn it into an A without some... ahh... "creative" math

 

[Cindy B]

The way I had it calculated I would get a 91... actually a 90.5.

I think I was averaging them all without regard to weight.
Somehow I thought that the 40% (the 95%) would give me a higher grade average.

 

[shortbun]

87 is the actual score. It's a B average.

95+95+82+82+81 then divide by 5.

 

[cheeringmom]

I screwed up on my dd's grade calculation too. I thought she had a 3.5 and she corrected my mistake which gave her a 3.71. I definately need a refresher in my math skills! Too much playskool and little tykes going on in my house!!

I'm loosing brain cells!!

 

[mickeyboat]

Math ... Huh?

Denae

 

[Cindy B]

Originally posted by shortbun
87 is the actual score. It's a B average.

95+95+82+82+81 then divide by 5.

Where does that second 95 come into play?

 

[jrydberg]

Because the 571/600 is worth 40% of the total, whereas the others are worth 20%.

 

[Rajah]

Another way to do it:

571/600 * 100= 95.167

Since that's 40%, add it 4 times and the other two grades 2 times each:

95.2 + 95.2 + 95.2 + 95.2 + 81 + 81 + 82 + 82 + 82 + 82 = 870.8

Take that and divide by 10 and you get 87.08

 

[Cindy B]

Originally posted by Rajah
Another way to do it:

571/600 * 100= 95.167

Since that's 40%, add it 4 times and the other two grades 2 times each:

95.2 + 95.2 + 95.2 + 95.2 + 81 + 81 + 82 + 82 + 82 + 82 = 870.8

Take that and divide by 10 and you get 87.08

See, I was taught that method as well. I messed up the calculations along the way.. so I got a 90 instead of an 87.

 

[ThreeCircles]

Can we do some quadratic equations now?

I always did love those!