Question 929407
Count the prime numbers from 1 to 25. (2,3,5,7,11,13,17,19,23). 9 of them
Count the numbers greater than 20. (21,22,23,24,25). 5 of them
Count the numbers in both groups: (23). 1 of them.
So then,
{{{P=(9+5-1)/25=13/25}}}