We just need to work both numerator and denominator.
Both numbers are even numbers, so both of them can be divided by 2:
So far the fraction has been simplified from 20/32 to 10/16. However, it can be simplified further, since again, 10 and 16 are both even numbers:
Now we have simplified the fraction 20/32 to 5/8. This can not be simplified further since 5 and 8 do not have a common divisor other than 1.
Then, the answer is 5/8.