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CBSE · Class 9 · Mathematics

The Mathematics of Maybe: Introduction to Probability

Standard difficulty · 20 questions · 40 marks

Name: Date: Score: ____ / 40

Show your working for Sections B and C. Answers are on the last page — try every question first!

Section A — Choose the correct answer8 × 1 = 8 marks
1.
A die is thrown once. The probability of getting an odd number is:
  1. 1/4
  2. 1/2
  3. 1/3
  4. 2/3
2.
Two coins are tossed together. The probability of getting at most one head is:
  1. 3/4
  2. 1/4
  3. 3/8
  4. 3/5
3.
A bag has 14 red, 14 blue and 10 green balls. One ball is drawn at random. The probability that it is blue is:
  1. 15/38
  2. 7/38
  3. 7/19
  4. 12/19
4.
A card is drawn from a well-shuffled deck of 52 cards. The probability that it is a red card is:
  1. 25/52
  2. 1/4
  3. 1/2
  4. 27/52
5.
The probability of an impossible event is:
  1. −1
  2. 1
  3. 1/2
  4. 0
6.
If P(E) = 0.44, then P(not E) is:
  1. 0.56
  2. 0.52
  3. 0.44
  4. 0.6
7.
Two dice are thrown together. The probability of getting a doublet (the same number on both) is:
  1. 7/36
  2. 5/6
  3. 1/12
  4. 1/6
8.
Assertion (A): When a die is thrown, the probability of getting an odd number is 1/2.
Reason (R): The probability of an event can be greater than 1.
  1. Both A and R are true, and R is the correct explanation of A.
  2. Both A and R are true, but R is not the correct explanation of A.
  3. A is true, but R is false.
  4. A is false, but R is true.
Section B — Short answer8 × 2 = 16 marks
9.
A box has discs numbered 1 to 60. One disc is drawn at random. Find the probability that its number is a prime number.
10.
All the spades are removed from a deck of 52 cards. One card is drawn from the rest. Find the probability that it is a face card.
11.
Two dice are thrown. Find the probability that the product of the numbers is 2.
12.
A box of 290 bulbs has 48 defective bulbs. One bulb is taken at random. Find the probability that it is not defective.
13.
A letter is chosen at random from the word CALCULATOR. Find the probability that it is a vowel.
14.
Three coins are tossed together. Find the probability of getting more heads than tails.
15.
A jar has 66 marbles. The probability of drawing a red marble is 5/6. How many red marbles are there?
16.
A spinner has 9 equal sectors numbered 1 to 9. Find the probability that it stops on an odd number.
Section C — Word problems4 × 4 = 16 marks
17.
In a lucky draw there are 750 tickets, of which 9 carry a prize. Dev buys one ticket. Find the probability that Dev wins a prize, and that Dev does not.
18.
A crate has 190 mangoes, of which 27 are rotten. A shopkeeper picks one at random. What is the probability that it is good?
19.
Zoya and Dev play a game: two dice are thrown, and Zoya wins if they show a total of more than 9. Otherwise Dev wins. Find the probability that Dev wins.
20.
A lot of 400 shirts has 369 good shirts, 21 with minor defects and 10 with major defects. Jimmy buys only a good shirt; Sujatha refuses only shirts with major defects. A shirt is drawn at random. Find the probability that it is acceptable to (i) Jimmy, (ii) Sujatha.
AmbifulWorksheets
Practice that never repeats
CBSE · Class 9 · Mathematics

Answer key

The Mathematics of Maybe: Introduction to Probability · AW-9M-PRB-2026-V1 · For parents — fold back or tear off before handing the sheet to your child.

QAnswerWorking
1(b) 1/23 favourable outcomes out of 6
2(a) 3/4outcomes HH, HT, TH, TT: 3 favourable
3(c) 7/1914 blue out of 38
4(c) 1/226 such cards out of 52
5(d) 0—
6(a) 0.561 − 0.44 = 0.56
7(d) 1/66 favourable outcomes out of 36
8(c) A is true, but R is false.A is true: 3 of the 6 outcomes are favourable. R is false.
917/6017 such numbers from 1 to 60
103/1339 cards are left, and 9 of them are face cards
111/18pairs with product 2: 2 out of 36
12121/145290 − 48 = 242 good bulbs out of 290
132/54 vowels among 10 letters
141/28 outcomes (HHH, HHT, …, TTT); 4 favourable
1555 red marbles5/6 × 66 = 55
165/95 of the 9 numbers
173/250; 247/2509 out of 750; 1 − 3/250
18163/190163 good out of 190
195/6Zoya wins in 6 of 36 outcomes; Dev in 30
20(i) 369/400 (ii) 39/40Jimmy: 369 of 400; Sujatha: 390 of 400