Answer:
7
Step-by-step explanation:
First, add all the cards.
[tex]2 + 5 + 7 + 8 + 9 = 31[/tex]
If we remove one card, the remaining four cards average will be 6, this means that the 4 remaning cards will average total will be at 24 because 6×4=24. So we need to find a value that will equal 24 if we remove that card.
The answer is 7 because
[tex] \frac{2 + 5 + 8 + 9}{4} = 6[/tex]
9514 1404 393
Answer:
remove 7 to make the total be 6×4 = 24.
Step-by-step explanation:
The description "mean average" is redundant to no apparent purpose. "Mean" and "average" are the same thing: the total divided by the number of contributors.
If the mean of 4 cards is 6, then we require ...
6 = (total of 4 cards) ÷ 4
24 = total of 4 cards . . . . . . . multiply both sides of the equation by 4
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We note that the total of all the cards shown is ...
2 + 5 + 7 + 8 + 9 = 31
In order to make the total be 24, we need to remove a card that has a value of ...
31 -24 = 7
Removing 7 will bring the total to 2 + 5 + 8 + 9 = 24, and the average to 24/4 = 6.
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Additional comment
It is worthwhile to remember the relationship between the total and the average and the number of contributors. This shows up a lot in problems involving adjusting an average or finding a value to give a certain average.