SOLUTION: Here is the word problem I am trying to write an equation for:
" Mike received 73%, 71%, 79% and 75% on his first four math tests. What grade on his fifth test would allow him
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" Mike received 73%, 71%, 79% and 75% on his first four math tests. What grade on his fifth test would allow him
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Question 572864: Here is the word problem I am trying to write an equation for:
" Mike received 73%, 71%, 79% and 75% on his first four math tests. What grade on his fifth test would allow him to make an average of at least 75%? Assume the test scores are whole numbers."
Here is what I have tried so far:
Let X represent fifth test score
(73 +71+79+75 + X)/5 = 75
(298 + X)/5 = 75
59.6 + 1/5X = 75
X = (75 - 59.6)/5
X = 3.08
I know this is not correct but I am not sure what is wrong with my equation. Any help showing me how to set up the right equation would really help me. thanks
You can put this solution on YOUR website! " Mike received 73%, 71%, 79% and 75% on his first four math tests. What grade on his fifth test would allow him to make an average of at least 75%? Assume the test scores are whole numbers."
Here is what I have tried so far:
Let X represent fifth test score
(73 +71+79+75 + X)/5 = 75
----
(298+x) = 5*75
298+x = 375
x = 77
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Cheers,
Stan H.
You can put this solution on YOUR website! Here is what I have tried so far:
Let X represent fifth test score
(73 +71+79+75 + X)/5 = 75
(298 + X)/5 = 75
59.6 + (1/5)X = 75
X = (75 - 59.6)*5
X = 77
The sum of the scores of the 5 tests has to be 5 times the desired average. 5 times 75 is 375. The sum of the first 4 scores is 298. Subtract that from 375 to get 77.
You were actually on the right track:
is correct. At this point, I would have multiplied both sides by 5 to get rid of that pesky denominator, but there is really nothing wrong with your next step though.
is also correct, as is:
and
But right here is where you made your error. You were already dividing by 5 in the LHS, but then you chose to divide by 5 on the right (???).
what you wanted to do was multiply both sides by 5 to get:
John
My calculator said it, I believe it, that settles it
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