Question

Nancy wrote the following the riddle :I am a number between 25 and 50.my ones digit is three less than my tens digit . I am a prime number.

Answer 1

xy
x is tens
y is ones

hmm
it has to be more than 25, so the tens digit has to be at least 2 but less than 5
2-3=-1, no
3-3=0, 30 is a number
4-3=1, 41 is a number


30 and 41
30 is 3 times 10, it is not prime

41 is prime
41 is the answer