SOLUTION: pls. help me to answer: if the meanof three numbers is 20 and the mean of five numbers is 12, What is the mean of the eight numbers combined?

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Question 1107631: pls. help me to answer: if the meanof three numbers is 20 and the mean of five numbers is 12, What is the mean of the eight numbers combined?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +T%5B1%5D+ = the total of the 3 numbers
Let +T%5B2%5D+ = the total of the 5 numbers
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(1) +20+=+T%5B1%5D+%2F+3+
(2) +12+=+T%5B2%5D+%2F+5+
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(1) +T%5B1%5D+=+3%2A20+
(1) +T%5B1%5D+=+60+
and
(2) +T%5B2%5D+=+5%2A12+
(2) +T%5B2%5D+=+60+
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Let +M+ = the mean of the 8 numbers
+M+=+%28+T%5B1%5D+%2B+T%5B2%5D+%29+%2F+8+
+M+=+%28+60+%2B+60+%29+%2F+8+
+M+=+120%2F8+
+M+=+15+
The mean of the 8 numbers is 15