Answer:
A similar problem to yours is attached in the picture below. We adjust the data of the problem in the picture to fit your question.
The answer is (3/4)*(3/4)*(1/3) = 3/16 of the girls in the class have long brown hair and green eyes
Step-by-step explanation:
As every condition must contain the set we are studying, we are talking about and AND condition, and thus we need to multiply each term to get the correct result.
3/4 * (3/4) * (1/3) = 3/16
