Question

Winnie wrote the following riddle.I am a number between 60 and 100.My ones digit is two less than my tens digit.I am a prime number.

Answer 1

79

Explanation:

60<xy<100

y -2 =x

if it is prime

y cannot be even

so y could be 1,3,5,7,9

x would then be 9,1,3,5,7

but to be between 60 and 100

x must be 7 or 9

so the number must be 79 or 57

57 is not prime so

the number is 79