Page 356 - Start Up Mathematics_8 (Non CCE)

Answer in One Word or a Line
1. What is probability?
2. Define a random experiment.
3. Define the sample space of a random experiment.
4. How many cards are there in each suit of a pack of 52 cards?

let’s evaluate

1. Two fair dice are rolled simultaneously 67 times. A doublet is obtained 8 times. Now, if the pair of dice
are rolled simultaneously again at random, what is the probability of getting a doublet and probability of
not getting a doublet?
2. A box has coupons numbered from 1 to 100. A coupon is picked. Find the probability that the number
on the coupon is:
(a) even (b) a multiple of 3 (c) a prime number (d) a factor of 100
3. A bag contains 6 red marbles, 9 white marbles, 5 green marbles. What is the probability that if one marble
is taken out of the bag at random, it will be:
(a) red (b) white (c) not green
4. If there is a spinning wheel with 3-blue sectors, 1-red sector and 1-green sector of same size, what is the
probability of getting a blue sector?

Thinking Skills

1. Rahul notes the time when his bus has been coming for the last 11 days.
8:52 a.m. 8:48 a.m. 8:53 a.m. 8:59 a.m.
8:53 a.m. 8:49 a.m. 8:47 a.m. 8:46 a.m.
8:52 a.m. 8:57 a.m. 8:51 a.m.
If Rahul reaches his bus stop at 8:55, what is the probability that he has missed the bus?
2. What is the chance that an ordinary year selected at random will have 53 Sundays?

Values and Life Skills

A card is drawn from a well-shuffled deck of 52 cards. Find the probability of getting:
(a) a black card (b) a red card (c) a diamond card (d) a black number card
(e) a face card (f) an ace of hearts (g) a picture card
Give 2 reasons, why practice of playing cards with money on Diwali be curbed?

Exemplar Problems

1. In a school only, 3 out of 5 students can participate in a competition. What is the probability of the students
who do not make it to the competition?
(a) 0.65 (b) 0.4 (c) 0.45 (d) 0.6
2. A coin is tossed 200 times and head appeared 120 times. The probability of getting a head in this
experiment is:

2 3 1 4
(a) (b) (c) (d)
5 5 5 5
3. An experiment whose outcomes cannot be predicted exactly in advance is called a _______________
experiment.

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