In a classroom, 2/3 of the students have brown hair. furthermore, 2/5 have both brown hair and brown eyes. the probability that a brown haired student also has brown eyes equals ____.
A. 1/2
B. 2/3
C. 1/3
D. 3/5

I keep getting a different answer than the answers there. What am I doing wrong?

Question

In a classroom, 2/3 of the students have brown hair. furthermore, 2/5 have both brown hair and brown eyes. the probability that a brown haired student also has brown eyes equals ____. 
A. 1/2
B. 2/3
C. 1/3
D. 3/5

I keep getting a different answer than the answers there. What am I doing wrong?

ybarrap · Answer

Bayes Theorem:
P(brown eyes|brown hair) 
= P(brown eyes & brown hair)/P(brown hair)
=(2/5)/(2/3)
=3/5

Make sense?

anonymous · Answer

yes thank you! I doing it backwards

ybarrap · Answer

yw