0

Guest

Courses New

A box contains 10 red marbles, 20 blue marbles and 30 green marbles. 5 marbles are drawn from the box, what is the probability that (i) all will be blue? (ii) atleast one will be green?Can I have an easy explaination for how and why we use combination to do this

A box contains 10 red marbles, 20 blue marbles and 30 green marbles. 5 marbles are drawn from the box, what is the probability that (i) all will be blue? (ii) atleast one will be green?Can I have an easy explaination for how and why we use combination to do this

Grade:11

1 Answers

Arun
25757 Points
5 years ago
Dear student
 
Total number of ways for selecting 5 marbles out of 60 marbles n(S) = ⁶⁰C₅

(i) all will be blue .
Let E is the event all marbles will be blue then, 
n( E ) = 5 marbles out of 20 marbles = ²⁰C₅ 
so, P( E ) = n(E)/n(S) 
= ²⁰C₅ / ⁶⁰C₅

(ii) at least one will be green .
use formula , 
P(E') = 1 - P(E') 
e.g P(at least one green ) = 1 - P(no green )
but P( no green ) = P(red + blue ) = ³⁰C₅ / ⁶⁰C₅
so, P( at least one green ) = 1 - P(red + blue ) 
= 1 - ³⁰C₅ / ⁶⁰C₅
 
 
Regards
Arun (askIITians forum expert)

Think You Can Provide A Better Answer ?

Other Related Questions on Magical Mathematics[Interesting Approach]

View all Questions »

ASK QUESTION

Get your questions answered by the expert for free

Answer and earn gift vouchers

Win Gift vouchers upto Rs 500/-

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Click Here Know More

Complete Self Study Package designed by Industry Leading Experts

Click Here Know More

Live 1-1 coding classes to unleash the Creator in your Child

Click Here Know More

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Click Here Know More