Difference between revisions of "1990 AJHSME Problems/Problem 20"
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==Solution== | ==Solution== | ||
− | Let <math>S</math> be the sum of all the incomes but the largest one. For the actual data, the mean is <math>\frac{S+98000}{1000}</math>, and for the incorrect data the mean is <math>\frac{S+980000}{1000}</math>. The difference is <math>882\rightarrow \boxed{\text{ | + | Let <math>S</math> be the sum of all the incomes but the largest one. For the actual data, the mean is <math>\frac{S+98000}{1000}</math>, and for the incorrect data the mean is <math>\frac{S+980000}{1000}</math>. The difference is <math>882, or \rightarrow \boxed{\text{A}}</math> |
==See Also== | ==See Also== |
Latest revision as of 17:27, 7 May 2021
Problem
The annual incomes of families range from dollars to dollars. In error, the largest income was entered on the computer as dollars. The difference between the mean of the incorrect data and the mean of the actual data is
Solution
Let be the sum of all the incomes but the largest one. For the actual data, the mean is , and for the incorrect data the mean is . The difference is
See Also
1990 AJHSME (Problems • Answer Key • Resources) | ||
Preceded by Problem 19 |
Followed by Problem 21 | |
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All AJHSME/AMC 8 Problems and Solutions |