In a large general education class, 70% (0.7) are science majors, and 30% (0.3) are liberal arts majors. Sixty percent (0.6) of the science majors are seniors, while 50% (0.5) of the liberal arts majors are seniors.
(a) If there are 200 students in the class, how many of them are science majors?

(b) If there are 200 students in the class, how many of them are science majors and seniors?

Question

In a large general education class, 70% (0.7) are science majors, and 30% (0.3) are liberal arts majors. Sixty percent (0.6) of the science majors are seniors, while 50% (0.5) of the liberal arts majors are seniors.
(a) If there are 200 students in the class, how many of them are science majors?


(b) If there are 200 students in the class, how many of them are science majors and seniors?

anonymous · Answer

a. 200*0.7 = 140
b. 0.7*0.6*200 = 84

anonymous · Answer

oh yes i got the first one right thanks.

hero · Answer

You can't do it like that. You have to use Euler Diagram