# Yesterday's SAT Practice ?

<p>I don't understand why you would multiply the total of marbles by the average cost. Isn't the average cost not exact? How will you get the exact total cost by multiplying the total marbles with average cost?</p>

<p>Look, there are 3 bags total right?
The 3 bags each have a certain amount - 20, 50 and 100 marbles.
To find the average cost per marble you need to divide the total combined cost for all 3 bags of marbles by Total number of marbles </p>

<p>You get this equation: (2+4+x)/(20+50+100) = .08 Solve for X</p>

<p>Well my key problem is the average cost per marble. The average isn't what each marble costs! It's just an average right?</p>

<p>So like, say you had 3 test scores. one was 70, was was 80 and one was 35.
The average of these is about 62%. But that's not was each test score was. IDK how to explain the way i'm reasoning it..</p>

<p>The question is confusing, I admit. At first, I thought they were asking for the average cost of the cost per marble of the three bags...</p>

<p>So, I was trying (2/20+4/50+x/100)/3 = 0.08</p>

<p>Then I realized maybe they meant the average of ALL the marbles COMBINED. :D</p>

<p>The question isn't confusing at all...</p>

<p>Go look up the word average. Or go learn English or something...</p>

<p>The average of the 3 test scores is 61.6666. If you take that number and you multiply by 3, you get the total combined score on the 3 tests.</p>

<p>Yes, but I was looking at the average of the costs of ONE piece from each bag. That is to say, the average of the different costs of marbles.</p>

<p>If I didn't know the meaning of average, I would hardly be able to do that, would I? And if I didn't know English, I wouldn't be able to type this, would I?</p>

<p>I was talking to the OP.</p>