Ms. Morris needs 2 students to help her with a demonstration for her class of 12 girls and 14 boys. She randomly chooses 2 students. What is the probability that she chooses 2 girls.

Question

anonymous · Answer

12/26 ->6/13-> about 0.46%

anonymous · Answer

if you need any more help just ask

anonymous · Answer

i thought that was the probabilty of choosing one girl.

anonymous · Answer

sorry i think i made a mistake

anonymous · Answer

just give me a minute i get it

anonymous · Answer

ok

anonymous · Answer

turns out i was right, i checked the same problem posted by somebody else, they got the same answer as mine. here where i checked it : http://openstudy.com/study#/updates/4f6176ace4b079c5c630f963

anonymous · Answer

so do you still need anything else???

anonymous · Answer

I checked the link you sent me.  The question asked what is the probablity of choosing one girl.  Mine is choosing 2 girls.  I don't think  the answer is the same.

anonymous · Answer

oh huh what you know. Well this is embarring. hold on i'll see if we can get some help on this.

apoorvk · Answer

This one @tim538

anonymous · Answer

huh ???

apoorvk · Answer

I mean 'this one?"

anonymous · Answer

oh yeay

apoorvk · Answer

Ohkay- so what you folks were wasn't exactly right.

It's this way actually:
probability of selecting a girl out 26 students, when 12 are girls = 12/26

now 25 students are left after this, and 11 girls remain.
so, picking up another girl out of 25 students, when 11 are girls = 11/25

so, the probability of both events happening simultaneously = (12/26)*(11/25)

anonymous · Answer

Wouldnt it be 10/24 if the teacher was picking two girls?

apoorvk · Answer

alternatively, ways of choosing two girls from 12 = 12C2 = favorable outcome
ways of picking any 2 students out of 26 students = 26C2 = sample space

so, P = (no. of favorable outcome)/(sample space) = (12C2)/(26C2)

The answer would be the same in both methods.

apoorvk · Answer

You mean for the third girl?

apoorvk · Answer

how did you get that '10' and '24'?

anonymous · Answer

Oh never mind, I messed up.

anonymous · Answer

@apoorvk that some smart thinkin there.

apoorvk · Answer

@aeroboy understand now? :)

Lol, nothing smart about that, @tim538 :)

anonymous · Answer

Yes, thank you.

apoorvk · Answer

@tim538 I really appreciate you're truly trying to help people, and not just giving away answers :)

anonymous · Answer

just trying to do what you do :)

apoorvk · Answer

lol, i don't do much :P

anonymous · Answer

and tim538, thank you for trying to help me.

anonymous · Answer

your welcome ;)