Teesha is in the French club. There are 29 students in the club. The French teacher will pick two students at random to guide visiting students from France. What is the probability that Teesha will not be picked as a guide?

Question

hartnn · Answer

what is with this question today ?

terenzreignz · Answer

Pandemic :D
Do the honours, @hartnn ?
Link :D

terenzreignz · Answer

Who in the blazes is Teesha, and why is it important that she be left out as a guide? :D

hartnn · Answer

instead of linking, i'll copy the explanation here,

hartnn · Answer

the probability that Teesha will not be picked as a guide means 
Teesha will not be picked on 1st selection 
AND 
Teesha will not be picked on 2nd selection 

1st selection : 
the teacher has 29 options and to NOT select teesha, there are 28 other choices,
so 28/29 for 1st seletion, 

2nd selection : 
now there are 28 others left to select from, and to NOT select teesha, there are 27 other choices, 
so, 27/28 for 2nd selection.

since these selections are independent, you'll multiply them, 

28/29 * 27/28 =.... ?

anonymous · Answer

if theres 29 total and they take 2 would it be . . ..

anonymous · Answer

am i supposed to times that @hartnn

hartnn · Answer

not actually...read my explanation and tell me if you have doubts anywhere...

anonymous · Answer

This is hard.

hartnn · Answer

maybe because you are seeing entire explanation at once.... ?

the probability that Teesha will not be picked as a guide means 
Teesha will not be picked on 1st selection 
AND 
Teesha will not be picked on 2nd selection

this makes sense ?

anonymous · Answer

is it 27/29

hartnn · Answer

yes, but understanding how to get there is more important, so that you can solve similar questions on your own...

anonymous · Answer

I undersyand because i went back and re-read what you said Thank you very much

hartnn · Answer

hmm...welcome :)