Jerry's average

G

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Another problem I'm stuck on...*sigh* why am I even in Honors?

Jerry has recieved the following math test scores: 80, 75,79,86. His final exam is worth points and counts as 2 tests. What is the lowest score he can get to keep an average of at least 80 points? Explain your strategy.

I've done: (80+75+79+86 / 4) + (2x/2) >= 80

somehow...that equation isnt working

the 2x/2 is for taking the one 200 point test and making it into two 100 point test..like it said (didnt it?). :?

I wouldn't be surprised if youre looking at this and shaking your head thinking that I'm really dumb. It seems like a really easy problem but i just dont understand how to work it out.
 
You were on the right track, but took a wrong turn. If the final counts as two tests, then how many tests, effectively, will there have been? If you're taking the average of all of those tests, then don't you need to add them all together, and divide them all by the same value?

Eliz.
 
there would be six tests? so would i do:

80 + 75+ 79+ 86 + 2x / 6 = 80?
 
To check the answer of any "solving" problem, plug it back into the original question. If he gets an 80 on the last test, which counts like two tests (so it's like he got an 80 on two tests), would his average score on the five tests (which count as six tests) be 80? If the answer is "yes", then your solution is correct.

Eliz.
 
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