2003 AMC 10B Problems/Problem 24
Problem
The first four terms in an arithmetic sequence are , , , and , in that order. What is the fifth term?
Solution
The difference between consecutive terms is Therefore we can also express the third and fourth terms as and Then we can set them eual to and because they are the same thing.
Substitute into our other equation.
But cannot be because then every term would be equal to Therefore Substituting the value for into any of the equations, we get Finally,
See Also
2003 AMC 10B (Problems • Answer Key • Resources) | ||
Preceded by Problem 23 |
Followed by Problem 25 | |
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