Brain Teasers
Primes by Primes
Consider two-digit prime numbers. Whenever you add the two digits you get a number which is not prime i.e. It may be divisible by 2,3, etc. However there are only five two-digit prime numbers whose digits when added give a result that is divisible by 5. Three are 19,23 and 73.
Can you find the other two prime numbers whose digits add up to a number divisible by 5?
Can you find the other two prime numbers whose digits add up to a number divisible by 5?
Answer
They are 37 and 41.Hide Answer Show Answer
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