Which are Semirps?

1 ⤊

Semirps: 2, 3, 11, 23, 53, 97, 71, 47
Not: 15, 21, 25, 39, 190, 209

Which are Semirps?:
123, 51, 67, 27

2006-09-12 12:09:00 · 3 answers · asked by fye1991 2 in Science & Mathematics ➔ Mathematics

3 answers

Your clue is reading the word backwards. 'Semirp' backwards is 'primes'.

And indeed... all the 'semirps' listed ARE prime numbers.

So of your second group, only 67 is prime, and a 'semirp'.

2006-09-12 12:12:49 · answer #1 · answered by Doctor Why 7 · 1⤊ 0⤋

Just 67 is prime. 123=3*41, 51=3*17 and 27=3*3*3=3^3

2006-09-12 19:42:05 · answer #2 · answered by Arash 3 · 0⤊ 0⤋

Fermi has nailed it -- give him the points.

2006-09-12 19:34:02 · answer #3 · answered by Anonymous · 0⤊ 0⤋