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### Someone ans it.

Posted: Wed Feb 20, 2019 8:55 am
Imagine you have \$5\$ green and \$5\$ blue balls in a box. 2 balls are taken from the box what is the probability of at least one ball will be blue. What is the probability of those two balls will green

### Re: Someone ans it.

Posted: Wed Feb 20, 2019 9:11 am
Probablity of at least \$1\$ ball is blue=\$\dfrac{\dbinom{5}{1}×\dbinom {5}{1}+\dbinom {5}{2}x\dbinom {5}{0}

}{\dbinom {10}{2}}=\dfrac 79\$
Probablity of \$2\$ ball is green=\$\dfrac{\dbinom {5}{2}×\dbinom{5}{0}}{\dbinom {10}{2}}=\dfrac 29\$