Question

A box contains five balls numbered 1, 2, 3, 4, 5. Three balls are drawn randomly at the same time from the box.
(i) By listing all possible outcomes (123, 124, etc.), find the probability that the sum of the three numbers drawn is an odd number.
The random variable L denotes the largest of the three numbers drawn.
(ii) Find the probability that L is 4.

Answer 1

I've got the answer to (i) Help me up with (ii) will do.

Answer 2

how do you solve (i)

Answer 3

is it (1/2) * 5C3 * 3! ?

Answer 4

(I) or (ii)

Answer 5

(i)

Answer 6

No. You just list out all the possibilities without repeating the numbers first. Then you find which onene sums up to an odd number. The answer is 0.4

Answer 7

i got 1/3 for (ii)

Answer 8

Hahaha, no. Incorrect.

Answer 9

i) List all the different COMBINATIONS that you can get from the different numbers:
123
124
125
134
135
145
234
235
245
345

Now, technically each of these combinations will give you the same number of permutations since you are just finding the number of arrangements for 3 distinct elements every time. So, you find that 1+2+3 = even... keep doing that for every combination. Only 4 of the 10 combinations will give you an odd number

Answer 10

I've gotten the answer for i). I included it in there just incase you guys have to refer to it. Anyways, thanks.

Answer 11

ah.. sorry. I'll try ii)

Answer 12

It's okay. @kirbykirby :)

Answer 13

If you want L to be the largest of the three numbers, and that number must be 4, then you only need to consider the combinations 124, 134, 234... so there is a 3/10 probability

Answer 14

Ohh yeahhhh. Omg , it's that easy! THANKS man.

Answer 15

:)