RD Sharma solution class 7 chapter 25 Data Handling IV(Probability) Objective Type Questions

 Objective Type Questions

Page-25.7

Question 1:

An unbiased coin is tossed once, the probability of getting head is

(a) $\frac{1}{2}$                                  (b) 1                                         (c) $\frac{1}{3}$                                  (d) $\frac{1}{4}$

Answer 1:

Tossing a coin, either we get a head (H) or a tail (T). So, the probability of getting a head is $\frac{1}{2}$.
Hence, the correct option is (a).

Question 2:

There are 10 cards numbered from 1 to 10. A card is drawn randomly. The probability of getting
an even numbered card is

(a) $\frac{1}{10}$                                  (b) $\frac{1}{5}$                                         (c) $\frac{1}{2}$                                  (d) $\frac{2}{5}$

Answer 2:

The number on the cards are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
The even numbers on the cards are 2, 4, 6, 8, 10.
∴ Probability of getting an even numbered card = $\frac{\mathrm{Number} \mathrm{of} \mathrm{even} \mathrm{numbered} \mathrm{card}}{\mathrm{Number} \mathrm{of} \mathrm{cards} \mathrm{with} \mathrm{numbers} \mathrm{from} 1 \mathrm{to} 10}$

                                                                             $=\frac{5}{10}=\frac{1}{2}$
Hence, the correct option is (c).

Question 3:

A dice is rolled. The probability of getting an even prime is

(a) $\frac{1}{6}$                                  (b) $\frac{1}{3}$                                         (c) $\frac{1}{2}$                                  (d) $\frac{5}{6}$

Answer 3:

The possible numbers on a dice are 1, 2, 3, 4, 5, 6.
There is only one even prime number which is 2.
∴ Probability of getting an even prime = $\frac{\mathrm{Number} \mathrm{of} \mathrm{even} \mathrm{prime} \mathrm{numbers}}{\mathrm{Number} \mathrm{of} \mathrm{all} \mathrm{possible} \mathrm{outcomes} \mathrm{on} \mathrm{the} \mathrm{dice}}$$=\frac{1}{6}$

                                                                            
Hence, the correct option is (a).

Question 4:

There are 100 cards numbered from 1 to 100 in a box. If a card is drawn from the box and
the probability of an event is $\frac{1}{2}$, then the number of favourable cases to the event is

(a) 20                                         (b) 25                                          (c) 40                                             (d) 50

Answer 4:

Here, $\frac{50}{100}=\frac{1}{2}$.
So, if the the probability of an event is $\frac{1}{2}$, then the number of favourable cases has to be 50.
Hence, the correct option is (d).

Question 5:

When a dice is thrown, the total number of possible outcomes is

(a) 6                                         (b) 1                                          (c) 3                                             (d) 4

Answer 5:

The number on the faces of a dice are 1, 2, 3, 4, 5, and 6.
∴ Number of possible outcomes = 6
Hence, the correct option is (a).

Question 6:

There are 10 marbles in a box which are marked with the distinct numbers from 1 to 10.
A marble is drawn randomly. The probability of getting prime numbered marble is

(a) $\frac{1}{2}$                                         (b) $\frac{2}{5}$                                          (c) $\frac{9}{3}$                                             (d) $\frac{3}{10}$
 

Answer 6:

The numbers marked on the marbles are 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.
Here, the prime numbers (favourable outcomes) are 2, 3, 5, and 7.
∴ Number of favourable outcomes = 4
Therefore
Probability of getting prime numbered marble = $\frac{4}{10}=\frac{2}{5}$
Hence, the correct option is (b).

Question 7:

The probability of getting a red card from a well shuffled pack of cards is

(a) $\frac{1}{4}$                                         (b) $\frac{1}{2}$                                      (c) $\frac{3}{4}$                                             (d) $\frac{1}{3}$

Answer 7:

There are 52 cards in a standard deck. There are four different suits Diamonds (red), Clubs (black)
, Hearts (red), and Spades (black) each containing 13 cards.
∴ Number of red cards (favourable outcomes) = 13 + 13 = 26
Therefore
Probability of getting a red card = $\frac{26}{52}=\frac{1}{2}$
Hence, the correct option is (b).

Question 8:

A coin is tossed 100 times and head is obtained 59 times. The probability of getting a tail is

(a) $\frac{59}{100}$                                         (b) $\frac{41}{100}$                                      (c) $\frac{29}{100}$                                             (d) $\frac{43}{100}$

Answer 8:

Number of all possible outcomes = 100
Number of head obtained = 59
Number of tail obtained (favourable outcomes) = 100 − 59 = 41
Therefore
Probability of getting a tail = $\frac{41}{100}$
Hence, the correct option is (b).

Question 9:

A dice is tossed 80 times and number 5 is obtained 14 times. The probability of not getting the number 5 is

(a) $\frac{7}{40}$                                         (b) $\frac{7}{80}$                                      (c) $\frac{33}{40}$                                             (d) None of these

Answer 9:

Probability of getting 5 = $\frac{14}{80}=\frac{7}{40}$
Therefore
Probability of not getting 5 = $1-\frac{7}{40}=\frac{33}{40}$
Hence, the correct option is (c).

Question 10:

A bag contains 4 green balls, 4 red balls and 2 blue balls. If a ball is drawn from the bag, the
probability of getting neither green nor red ball is

(a) $\frac{2}{5}$                                         (b) $\frac{1}{2}$                                      (c) $\frac{4}{5}$                                             (d) $\frac{1}{5}$

Answer 10:

The probability of getting neither green nor red ball is equal to the probability of getting blue balls.
Number of blue balls = 2
Total number of balls = 4 + 4 + 2 = 10
Therefore
Probability of getting neither green nor red ball = $\frac{2}{10}=\frac{1}{5}$
Hence, the correct option is (d).