Question

A box contains 7 red balls, 8 green balls and 5 white balls. A ball is
drawn at random from the box. Find the probability that the ball is:
) white
b) neither red nor white.

​

Answer 1

✯✯ QUESTION ✯✯

A box contains 7 red balls, 8 green balls and 5 white balls. A ball is drawn at random from the box. Find the probability that the ball is:

a) white

b) neither red nor white.

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✰✰ ANSWER ✰✰

$⇝Red\:Balls=7$

$⇝Green\:Balls=8$

$⇝White\:Balls=5$

☞$Total\:Balls=20$

(a)White Balls

➳$Probability=\dfrac{No.\:of\:fav.\:Outcomes}{Total\:no.\:of\:Outcomes}$

$⇝\cancel\dfrac{5}{20}⟹\dfrac{1}{4}$

(b)neither red nor white

$⇝Total\:Balls-Red\:balls-White\:Balls$

$⇝20-7-5$

$⇝8\:balls$

☞$Probability=\dfrac{No.\:of\:fav.\:Outcomes}{Total\:no.\:of\:Outcomes}$

☛$\cancel\dfrac{8}{20}⟹\dfrac{2}{5}$

Answer 2

$\huge\purple{ \underline{ \boxed{\mathbb{\red{QUESTION : }}}}}$

A box contains 7 red balls , 8 green balls and 5 white balls. A ball is drawn at random from the box . Find the probability that the ball is :

a) white

b) neither red nor white.

$\huge\purple{ \underline{ \boxed{\mathbb{\red{ANSWER : }}}}}$

Probability that the ball is white = 0.25

Probability that the ball is neither red nor white = 0.4

$\huge\purple{ \underline{ \boxed{\mathbb{\red{EXPLANATION : }}}}}$

$\green{ \large \underline{ \mathbb{\underline{GIVEN : }}}}$

• No. of red balls = 7

• No. of green balls = 8

• No. of white balls = 5

$\green{ \large \underline{ \mathbb{\underline{TO \: FIND : }}}}$

The probability that the ball is :

• a) white

• b) neither red nor white.

$\green{ \large \underline{ \mathbb{\underline{FORMULA \: USED: }}}}$

$\displaystyle\purple{ \boxed{ \textsf{Probability}= \frac{ \textsf{No. of favourable outcomes}}{ \textsf{Total no. of outcomes}} }}$

$\green{ \large \underline{ \mathbb{\underline{SOLUTION: }}}}$

Total no. of balls = No. of red balls + No. of green balls + No. of white balls

Total no. of balls = 7 + 8 + 5

Total no. of balls = 20

$\green{ \bf \underline{ \mathbb{\underline{a ) \: WHITE \: \: BALLS: }}}}$

$\displaystyle\sf Probability= \frac{ \textsf{No. of favourable outcomes}}{ \textsf{Total no. of outcomes}}$

$\displaystyle \longrightarrow\sf Probability= \frac{ \textsf{5}}{ \textsf{20}} \: \: \: \\ \\ \displaystyle \longrightarrow\sf Probability= \frac{1}{4} \: \: \: \: \: \\ \\ \displaystyle \longrightarrow\sf Probability= 0.25$

$\green{ \bf \underline{ \mathbb{\underline{b) \: NEITHER \: RED \: NOR \: WHITE: }}}}$

No. of neither red nor white balls = Total no. of balls - No. of red balls - No. of white balls

No. of neither red nor white balls = 20 - 7 - 5

No. of neither red nor white balls = 8

$\displaystyle\sf Probability= \frac{ \textsf{No. of favourable outcomes}}{ \textsf{Total no. of outcomes}}$

$\displaystyle \longrightarrow\sf Probability= \frac{ \textsf{8}}{ \textsf{20}} \: \: \: \\ \\ \displaystyle \longrightarrow\sf Probability= \frac{2}{5} \: \: \: \: \: \\ \\ \displaystyle \longrightarrow\sf Probability= 0.4 \: \:$