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A bag contains $5$ red, $8$ white and $7$ black balls. If A ball is drawn at random from the bag. Then Find the probability that the drawn ball is (i) red or white (ii) not black
A bag contains $5$ red, $8$ white and $7$ black balls. If A ball is drawn at random from the bag. Then Find the probability that the drawn ball is (i) red or white (ii) not black
CBSE | Class 10 | Exercise 13.1 | Maths | Probability | RD Sharma
A bag contains $5$ red, $8$ white and $7$ black balls. If A ball is drawn at random from the bag. Then Find the probability that the drawn ball is (i) red or white (ii) not black

As we know that;

Total number of possible outcomes $=20$ ($5$ red, $8$ white & $7$ black}

(i)  Let E = event of drawing a red or white ball

So, No. of favorable outcomes $=13(5$ red $+8$ white)

Therefore Probability, P(E) = Number of favorable outcomes/ Total number of outcomes

P(E) = 13/20

(ii) Now Let E = event of getting a black ball

No. of favorable outcomes $=7$($7$ black balls)

Thus, Probability, $P(E)=$ Number of favorable outcomes/ Total number of outcomes

P(E)$=7/20$

$\overset{\scriptscriptstyle\rightharpoonup}{E}=$Event of not getting black ball

$P(\overset{\scriptscriptstyle\rightharpoonup}{E})=1-P(E)$

$P(\overset{\scriptscriptstyle\rightharpoonup}{E})=1-\frac{7}{20}$

$P(\overset{\scriptscriptstyle\rightharpoonup}{E})=\frac{13}{20}$

i

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