When turning a ratio into a fraction you simply use the first number as the numerator(the number on top) and the other number as the denominator(the bottom number) and then you simplify the answer as much as possible. So your answer would be 2/3. Both numbers can be divided by 8 16/8 is 2(the numerator) and 24/8 is 3( the denominator)
You can simplify the fraction by dividing by 8, so 16/8=2 and 24/8=3, and 2/3 is the most simplified it can be, if you need more information on how I did this, I'll be glad to explain better :)
