# Average test score problem...

#### flybry2000

10+ Year Member
5+ Year Member
Who wants to help me with this one? If you get it right you will get a 34 in the QR section...

In a given course a student recieves prelimenary exmination scores of 81,81 and 95. The final examination is weighed for one-third and the average of the prelimenary grades is weighed as 2/3 of the final grade. What should the final examination grade be for a semester average of 90?

A) 99
B) 96
C) 93
D) 88
E) 87

Grazi

Flybry2000

10+ Year Member
Well you would solve it by using (Average preliminary)(2/3) + (final)(1/3) = 90

So if you solve it (81+81+95)/3 * (2/3) + (x)*(1/3) = 90
I got x= 98.67

If you plug in the answer for B 96 as the x value, this gives a final grade of 89.1111

I would say the problem is wrong. Unless I did something wrong.

#### RCT PC CRN

##### RCT-PC-CRN
I got 99 too. Answer is A

OP
F

#### flybry2000

10+ Year Member
5+ Year Member
Alright guys,

Here's what I've come up with. My Lab partner used to be a teacher, so I knew she would know this one. The answer is not 99, which is what I was getting the first time around as well. So first you take the average of pre-lims (81+85+950/3= 87. Then you go: 2/3(87)+1/3*x=90 Rearrange:1/3*x=32 x=96

Thx for the posts! (you to RCT PC CRN) I've seen you answer alot of my questions!

10+ Year Member
Alright guys,

Here's what I've come up with. My Lab partner used to be a teacher, so I knew she would know this one. The answer is not 99, which is what I was getting the first time around as well. So first you take the average of pre-lims (81+85+950/3= 87. Then you go: 2/3(87)+1/3*x=90 Rearrange:1/3*x=32 x=96

Thx for the posts! (you to RCT PC CRN) I've seen you answer alot of my questions!

Why are you using 81, 85, and 95 as the preliminary scores? In the first post it says 81, 81, 95... unless you made a typo?

#### Maygyver

10+ Year Member
5+ Year Member
Why are you using 81, 85, and 95 as the preliminary scores? In the first post it says 81, 81, 95... unless you made a typo?
Hah yeah. Maybe he did it wrong the first time because he used 81, 81 and 95. 99 is the answer if you use 81, 81 and 95.

Oh G

#### sfoksn

10+ Year Member
Wow. you need to get 98 on final to get 90 average ... when the final is worth 33% of the whole grade... Doesn't this make anybody else feel depressed? lol

OP
F

10+ Year Member
5+ Year Member