The mean of 4 numbers is 5 and the mean of 3 different numbers is 12. What is the mean of the 7 numbers together?

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Answer 1 · 2017-02-25T10:18:01

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The mean of a set of numbers is the sum of the numbers over the count of the set (the number of values).

We have a set of four numbers and the mean is 5. We can see that the sum of the values is 20:

$\frac{20}{4} = 5$ $20/4=5$

We have another set of three numbers whose mean is 12. We can write that as:

$\frac{36}{3} = 12$ $36/3=12$

To find the mean of the seven numbers together, we can add the values together and divide by 7:

$\frac{20 + 36}{7} = \frac{56}{7} = 8$ $(20+36)/7=56/7=8$