Question

A box contain 10 red balls , 20 yellow balls and 50 blue balls. If a ball is drwan at random from the box , find the probability that it will be
(i) a blue ball (ii) neither yellow nor blue

Answer 1

Total no of balls$=10+20+50=80$ $i.e,n\left(S\right)=80$

$\left(i\right)$ $P\left(E\right)=$getting a blue ball$=$$\frac{n\left(E\right)}{n\left(S\right)}$$=$$\frac{50}{80}=\frac{5}{8}$

$\left(ii\right)P\left(F\right)=$getting neither yellow nor blue$=$getting red$=$$\frac{n\left(F\right)}{n\left(S\right)}=\frac{10}{80}$$=$$\frac{1}{8}$