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Andrew and Maria each collected six rock...


Andrew and Maria each collected six rocks, and the masses of the rocks are shown in the table above. The mean of the masses of the rocks Maria collected is 0.1 kilogram greater than the mean of the masses of the rocks Andrew collected. What is the value of x ?

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The correct Answer is:
A, C
Since the mean of a set of numbers can be found by adding the numbers together and dividing by how many numbers there are in the set, the mean mass, in kilograms, of the rocks Andrew collected is `(2.4+2.5+3.6+3.1+2.5+2.7)/6=(16.8)/6`=2.8 . Since the mean mass of the rocks Maria collected is 0.1 kilogram greater than the mean mass of rocks Andrew collected, the mean mass of the rocks Maria collected is 2.8 + 0.1 = 2.9 kilograms. The value of x can be found by using the algorithm for finding the mean: `(x+3.1+2.7+2.9+3.3+2.8)/6=2.9`. Solving this equation gives x = 2.6, which is equivalent to 13 5 . Either 2.6 or `13/5` may be gridded as the correct answer.
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