Chapter 14: Probability
Unique Previous Year Questions extracted from the CBSE Class 10 Basic Mathematics 2025 question paper sets. Repetitive questions have been removed while retaining the major question types and variations.
I
Multiple Choice Questions
1. Conceptual – Sure Event
1 Mark
In a random experiment of throwing a die, which of the following
is a sure event?
Set 430/1/1
2. Basic Complementary Probability
1 Mark
If the probability of happening of an event is \(57\%\),
then the probability of non-happening of the event is:
Set 430/6/2
3. Balls – Complementary Event
1 Mark
A bag contains 3 red, 4 white and 7 green balls. A ball is drawn
at random. The probability that the ball drawn is
not of red colour is:
Set 430/1/2
4. Dice – Doublet
1 Mark
In an experiment of throwing a pair of dice, the probability of
not getting a doublet is:
Set 430/1/3
5. Dice – Total Outcomes
1 Mark
The total number of outcomes in the experiment of simultaneous
throw of three dice is:
Set 430/2/1
6. Dice – Sum at Least 9
1 Mark
A pair of dice is thrown simultaneously. Let \(E\) denote the event
that the sum of numbers obtained on both dice is at least 9.
The number of outcomes in favour of event \(E\) is:
Set 430/3/1
7. Dice – Sum More Than 9
1 Mark
Two dice are rolled together. The probability of getting a sum
more than 9 is:
Set 430/6/3
8. Dice – Algebraic Relation
1 Mark
Two dice are rolled together. The probability of getting an outcome
\((a,b)\) such that \(b=2a\), is:
Set 430/6/2
9. Coins – Exactly One Tail
1 Mark
Three coins are tossed together. The probability that only one
coin shows tail is:
Set 430/4/1
10. Coins – At Least One Head
1 Mark
Three coins are tossed together. The probability that at least one
head comes up is:
Set 430/6/3
11. Cards – Specific Number
1 Mark
A card is drawn at random from a well shuffled deck of 52 playing
cards. The probability that the drawn card shows number \(9\) is:
Set 430/4/1
12. Cards – Lost Card
1 Mark
A black card is lost from a deck of 52 playing cards. The remaining
cards are shuffled and one card is drawn at random. The probability
that the drawn card is the king of hearts is:
Set 430/5/2
13. Decimal / Percent Relation
1 Mark
If \(E\) is an event such that \(P(E)=1\%\), then
\(P(\text{not }E)\) is equal to:
Set 430/5/2
II
Assertion – Reason Question
14. Complementary Probability
1 Mark
Assertion (A):
If \(E\) is an event such that
\(P(E)=\frac{1}{999}\), then
\(P(\text{not }E)=0.001\).
Reason (R):
\[
P(E)+P(\text{not }E)=1.
\]
III
Very Short Answer Type Questions
15. Figure Based – Geometric Probability
2 Marks
A coin is dropped at random on the rectangular region shown in
the figure. The rectangle measures \(3\,m\times2\,m\), and a circle
of radius \(0.7\,m\) lies inside it.
What is the probability that the coin will land inside the circle?
Set 430/4/1
16. Dice – Two Conditions
2 Marks
A die is thrown twice. Find the probability that:
(i) the difference between the two numbers obtained is \(3\).
(ii) the sum of the numbers obtained is \(8\).
17. Algebraic Probability – Marbles
2 Marks
A bag contains 40 marbles out of which some are white and others
are black. If the probability of drawing a black marble is
\(\frac{3}{5}\), find the number of white marbles.
Set 430/5/1
18. Cards – Prime and Perfect Square
2 Marks
In a pre-primary class, a teacher put cards numbered \(20\) to
\(59\) in a bowl. A student picked up a card at random and read
the number.
(i) Find the probability that the number read was a prime number.
(ii) Find the probability that the number read was a perfect square.
19. Numbered Discs – Two Conditions
2 Marks
A box contains 120 discs, numbered from \(1\) to \(120\). If one
disc is drawn at random, find the probability that:
(i) it bears a two-digit number.
(ii) the number is a perfect square.
IV
Short Answer Type Questions
20. Multi-Lot Pen Problem
3 Marks
A lot consists of 200 pens, of which 180 are good and the rest
are defective. A customer will buy a pen if it is not defective.
(i)
What is the probability that the customer will
not buy a pen drawn at random?
(ii)
Another lot of 100 pens containing 80 good pens is mixed
with the previous lot. What is the probability that the
customer will buy a pen drawn at random from the
entire lot?
21. Figure Based – Spinning Wheel
3 Marks
A game of chance consists of spinning a wheel which comes to rest
at one of the numbers from \(1\) to \(10\), as shown in the figure.
Find the probability that the wheel stops at:
(i) a prime number greater than \(2\)
(ii) an odd number less than \(9\)
(iii) a multiple of \(4\)
22. Mixed Marbles
3 Marks
A box contains 6 blue, 4 white and 8 red marbles. A marble is
drawn at random from this box. Find the probability that the
marble so drawn is:
(i) white
(ii) white or red
(iii) not red