### Brain Teasers

# Farm Dog

The numbers 2 and 5 are the only two prime numbers that end in 2 or 5. What is the rationale for the following groups of numbers?

3 17 31 47 61

7 19 37 49 67

11 23 41 53 71

13 29 43 59 73

3 17 31 47 61

7 19 37 49 67

11 23 41 53 71

13 29 43 59 73

### Answer

The numbers are grouped by column according to their BINGO letters (B = 1 through 15, I = 16 through 30, N = 31 through 45, G = 46 through 60, O = 61 through 75).Hide Answer Show Answer

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