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math. again, sorry. last one i promise.
this is my last math question, thank you guys so much.
Robert wants to have a mean of 150 for his bowling scores. He has bowled 137, 165, 142, and 139 in his first 4 games. He will bowl one more game. What is the least score that he can have in his fifth game to have a mean of 150?
133
143
157
167
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I'd answer this question in a different way, personally, using basic algebra instead of trial and error.
You know that...
150 = (137 + 165 + 142 + 139 + X ) / 5
So...
150 * 5 = 583 + X
So...
750 - 583 = X
So...
X = 167
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Okay, so you are trying to find the average. So basically, you want to add those 4 answers plus one of the choices, divide by 5...& the answer has to be 150 to be the correct answer:
a) 137 + 165 + 142 + 139 + 133 / 5 = 716 (incorrect)
b) 137 + 165 + 142 + 139 + 143 / 5 = 145.2 (incorrect)
c) 137 + 165 + 142 + 139 + 157 / 5 = 148 (incorrect)
d) 137 + 165 + 142 + 139 + 157 / 5 = 150
(correct answer).
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hey
the answer is 167.
this is what i did:
i added 137 + 165 + 142 + 139 & divided that number by 4 to find the average.
then, i added the total of the four numbers (583) & added each of the choices to 583. & divided each one by 5.
the only one that came up to 150 was 167.
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This is the easiest way I know how to do it. For five games to have an average of 150, the five scores have to add up to 750 [150*5=750]
The first four games add up to 583. 750-583= 167. So, he must bowl a game with a score of 167 to have an average of 150.
There's an exact equation. I don't remember exactly what it looks like, because I do things my own way in math. But your math book should have it in there, and the way I explained it to you is exactly what the equation does too.
hope I helped you though!
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