Chapter 7
The Mathematics of Maybe: Introduction to Probability
CBSE Class 9
Mathematics Solutions
Educart Mathematics class Class 9 NCERT Exemplar cover
Question:

Toss a coin 20 times and record the result each time (heads or tails).

(A) How many times did you get heads?

(B) How many times did you get tails?

(C) Calculate the experimental probability of getting heads.

(D) If you toss the coin once more, what is the probability of getting tails?                                        [Page No. 165]

Answer: Verified

(A) Say 11 heads.

(B) Tails = 20 - 11 = 9 tails.

(C) P(heads)=1120=0.55P(\text{heads}) = \frac{11}{20} = 0.55

(D) On the next (21st) toss, the probability of tails is still 12=0.5\frac{1}{2} = 0.5 (theoretical) for a fair coin.

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