The mean cost for each item in his bag was $3.05. he bought a total of 8 items, and the prices of 7 of those items are listed below: $2.75,$2.89,$3.57,$2.81,$3.37,$2.70 ,$2.48 determine the price of the 8th item in his bag.

You know the mean cost is calculated from ...

... (mean cost) = (total cost)/(number of items)

You are given the mean cost and the number of items, so you can find the total cost for the 8 items as ...

... (mean cost)×(number of items) = (total cost)

... 8 × $3.05 = (total cost) = $24.40

You are given the costs of 7 of the items so ...

... (total cost) = (8th item cost) + (total cost of 7 items)

Then we can find the (8th item cost) as ...

... (8th item cost) = (total cost) - (total cost of 7 items)

Adding up the given cost of the 7 items, we get ...

... (total cost of 7 items) = $20.57

... (8th item cost) = $24.40 -20.57 = $3.83

The price of the 8th item in the bag was $3.83.

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