Difference between revisions of "2007 AMC 12B Problems/Problem 18"
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Revision as of 23:20, 21 February 2008
Problem 18
Let , , and be digits with . The three-digit integer lies one third of the way from the square of a positive integer to the square of the next larger integer. The integer lies two thirds of the way between the same two squares. What is ?
Solution
The difference between and is given by
The difference between the two squares is three times this amount or
The difference between two consecutive squares is always an odd number. The consecutive squares with common difference are and . One third of the way between them is and two thirds of the way is
This gives , ,
See Also
2007 AMC 12B (Problems • Answer Key • Resources) | |
Preceded by Problem 17 |
Followed by Problem 19 |
1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | |
All AMC 12 Problems and Solutions |