Today Puzzle #622
Puzzle No. 622 鈥� Friday 29 November
A prime number is only divisible by itself and one. Today's date in short form is 29/11/19 - three prime numbers. How many times will this happen this century?
Today’s #PuzzleForToday has been set by Kyle Evans an award winning maths communicator and director of maths at Barton Peveril College
Click here for the answer
1300. There are 25 prime numbers under 100, so this phenomenon will only occur in years ending in 02, 03, 05, 07, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97. In these years there will be nine 'triple prime' dates in February, ten in November and eleven in March, May and July, so 52 per year. 25 x 52 = 1300.
(Note, if you thought 1 was a prime number, you would have got the answer 1794)
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