Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Pages: **1**

**Hannibal lecter****Member**- Registered: 2016-02-11
- Posts: 225
- Website

A university committee should have 5 members. There are 5 candidates from the computer department, and 10 candidates from the math dept.

a) Find the probability of event that 2 members would be from computer and 3 from math.

b) Is there a possibility that all the members are from math

c) Find the possibility that there is at least 1 person from computer

Wisdom is a tree which grows in the heart and fruits on the tongue

Offline

**bob bundy****Administrator**- Registered: 2010-06-20
- Posts: 8,386

hi Hannibal lecter

A university committee should have 5 members. There are 5 candidates from the computer department, and 10 candidates from the math dept.

a) Find the probability of event that 2 members would be from computer and 3 from math.

b) Is there a possibility that all the members are from math

c) Find the possibility that there is at least 1 person from computer

For (a) you need to calculate the probability of 2 from 5 (computer) and the probability of 3 from 10 (mathematics) and then put these together into a single probability.

I'll start you off with this:

P(2 from computers) = 5 / 15 x 4 / 14

But the same result can occur in 2 ways: eg. C1 followed by C2 or C2 followed by C1. So you're in danger of counting the same result twice. We avoid this by dividing by 2

P(2 from computers) = 5 / 15 x 4 / 14 ÷ 2

Then for the maths members you start with 10 / 13 and then continue for two more members. This time to avoid repetitions you need to divide by 6 as

M1M2M3, M1M3M2, M2M1M3, M2M3M1, M3M1M2, M3M2M1 all give the same three maths members.

Please have a go at finishing this off and post your working. I'll check it for you.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**Hannibal lecter****Member**- Registered: 2016-02-11
- Posts: 225
- Website

from where did you get the number 4 / 14 ???

and why didn't you use Combinations Or Permutations rules?

I'm so confused I can't imagine this

how could you avoid repetitions by just divide by 2 or 6!!! isn't there something called combinations without repetition or Permutations without repetition

I don't have a time they need the explanation please help me

*Last edited by Hannibal lecter (2018-03-09 06:09:36)*

Wisdom is a tree which grows in the heart and fruits on the tongue

Offline

**Hannibal lecter****Member**- Registered: 2016-02-11
- Posts: 225
- Website

Offline

Pages: **1**