I am a number who is greater than 40 and less than 90. I am proud to be a
prime number. My ones digit is also a prime number and so is my tens
digit. If you subtract my ones digit from my tens digit, the answer is not
2. What number am I?
2007-10-18 13:59:54 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
73
2007-10-18 14:09:57 · answer #1 · answered by Chuck Norris 2 · 0⤊ 0⤋
73.
If the teens digit is a prime number, that tells you that the number is in the 50's or 70's.
The ones digit being prime tells you that the ones digit is 3,5, or 7.
That leaves you considering 53,55,57,73,75,77.
57 & 75 are divisible by 3
55 & 77 are divisible by 11
53 can't be the answer because 5-3 is 2
That leaves 73.
2007-10-18 21:08:07 · answer #2 · answered by SoulDawg 4 UGA 6 · 0⤊ 0⤋
First find all the prime numbers between 40 and 90. (41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89)
Next eliminate all the numbers that have a non-prime number in the ones place. ( 41, 59, 61, 79, 89)
Remember that one is not considered a prime number...
Next eliminate all the numbers that have a non-prime number
in the tens place. ( 43, 47, 67, 83)
Finally eliminate the numbers whose difference in ones and tens is 2. ( 53)
This leaves you with 73
2007-10-18 21:11:43 · answer #3 · answered by Aaron R 2 · 1⤊ 0⤋
The answer is 52 because 5 is a prime number so it can only be divided by itself and 1 evenly and 2 is a prime number so it can only be divided by itself and 1 evenly. Also the number is greater than 40 and less than 90.
2007-10-18 21:10:18 · answer #4 · answered by abc 1 · 0⤊ 2⤋
51
2007-10-18 21:08:03 · answer #5 · answered by Chickee 2 · 0⤊ 0⤋
i think its 51.
2007-10-18 21:08:00 · answer #6 · answered by livefreexdiehardY 1 · 0⤊ 0⤋