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PrintDutch Mathematical Olympiad
Netherlands algebra
Problem
We order the positive odd integers as follows:
For each odd number we can determine in which row and column it is placed. For example, the number is placed in row and column . What number is placed in row and column ? A) B) C) D) E)
| column 1 | column 2 | column 3 | column 4 | column 5 | column 6 | ... | |
|---|---|---|---|---|---|---|---|
| row 1 | 1 | 3 | 11 | 13 | 29 | 31 | ... |
| row 2 | 5 | 9 | 15 | 27 | 33 | ... | |
| row 3 | 7 | 17 | 25 | 35 | ... | ||
| row 4 | 19 | 23 | 37 | ... | |||
| row 5 | 21 | 39 | ... | ||||
| row 6 | 41 | ... | |||||
| ... | ... |
Solution
D)
Final answer
D
Techniques
IntegersSums and products