Aptitude - Probability - Discussion

(10C1 x 15C2) why they are multiplying this ?

They should add the value know .. 10 c1 + 15 c2

@prabhu.

Even I have the same doubt. Can some intellectual person answer this?

I too have same doubt. Can any one clarify this, soon.

Because he asked 10 girls (and) 15 boys.

If they ask for same collections for example (a bag contains 6 white and 4 black balls.two balls are drawn at random.find the probability that they are of same color) here they are askin for same color in this case we have to use "+" i.e, 6c2+4c2

but here in a above problem they have tld us to select 1 girl out of 10 girls and 2 boys out of 15 boys.and here its not of same combination they are askin for both boy and gal.in this case we have to use "*" i.e, 10C1 x 15C2

Note tat: if its same color or combination go for "+"
If its different combination go for "*"

Nice explanation sanjana.

I solved this problem as
(10/25)*(15/24)*(14/23)

because 1st select 1 girl from 10 out of total 25 students, then 1 boy from 15 out of remaining 24 then again 1 boy from 14 boys and total remainig 23 students.... i got 7/46 as my ans.....

Can anyone please tell me whats wrong? please..

You got the Point @Abhi .. :-)

However I cannot help you in this. As I have no clue about is this a right method and robust to solve same kind of problem...??!

Help us.

And I Like this site. Appreciate it @IndiaBix.

Thanks sanjana.

I have a similar problem. Can anyone explain how to answer this: A class contains 7 women and 7 men. Suppose we choose three random students. How many ways can we choose exactly 1 woman?