Question

There are 40 elephants. 6 are blue, 8 black, 10 red, 6 yellow and 10 green. The 40 elephants are raced.

3 of the yellow elephants and tied together whilst 4 of the blue are tied toegher, what is the probability that these 7 elephants are in top 10?

Answer 1

33C3 * 7C7/ 40C10
6.44 * 10^(-6)

Answer 2

is this correct?

Answer 3

oh is it this simple.. so u dont have to form groups from the elephants that are tied together..
umm not sure.. was on test dunno ans

Answer 4

ya

Answer 5

@Ganpat im not sure :x

Answer 6

i can give a following try ,

3 yellow elephants are tied together from group of 6 = 6C3
4 blue elephant r tied together from group of 6 = 6C4

7 from a group of 40.. So, 40C7..

(6C3 * 6C4) / 40C7 ...

what say ?? i guess this might be right..

Answer 7

but thats not the prob of the 7 elephants in the first 10 is it ?

Answer 8

i swear we did this yesterday
or was it the day before?

Answer 9

different part 2

Answer 10

\[\frac{\left(\begin{matrix}33 \\ 3\end{matrix}\right)}{\left(\begin{matrix}33 \\ 3\end{matrix}\right)+\left(\begin{matrix}33 \\ 7\end{matrix}\right)+\left(\begin{matrix}33 \\ 6\end{matrix}\right)+\left(\begin{matrix}33 \\ 10\end{matrix}\right) }\] is ans

Answer 11

ok how they determined the denominator is looking at the 4 possible cases
-Both sets of tied elephants finish in top 10
- Only tied yellow elephants finish top 10
- Only tied blue elephants finish top 10
- Neither finish top 10

For each case, look at 33 choose n, where n is number of untied elephants who finish top 10

Answer 12

yeah i think i get it .. i dont think anyone got that on the test ..

Answer 13

haha i didn't either at first, i worked backwards after seeing the answer