Exercise 20
Question 1
1. A die is rolled once. What is the probability of rolling :
(a) 3
(b) 7
(c) an even number
(d) a prime number ?
2. Ramesh chooses a date at random in April for a party. Calculate the probability that he chooses
(a) a Saturday
(b) a Sunday
(c) a Saturday or a Sunday
3. A normal die is rolled. Calculate the probability that the number on the uppermost face when it stops rolling will be
(a) 5
(b) not 5
(c) an odd number
(d) a prime number
(e) a 3 or a 4
(f) a 1 or a 2 or a 3 or a 4 .
(g) an even prime number
4. A card is chosen at random from an ordinary deck of playing cards. What is the probability that
(a) a diamond is chosen?
(b) a king is chosen?
(c) a black 4 is chosen?
(d) a 7 of hearts is chosen?
5. Nine playing cards are numbered 2 to 10 . A card is selected from them at random. Calculate the probability that the card will be :
(a) an odd number
(b) a multiple of 4
6. This spinner is spun. What is the probability of getting
(a) a 1 ?
(b) not a 1 ?
(c) an odd number ?
(d) not an odd number ?
7. In a game at a fete a pointer is spun. You win the amount of money written in the sector where the pointer stops. Each sector is equally likely. Work out the probability that you win :
(a) no money
(b) $₹ 2$
(c) ₹ 6
(d) $₹ 10$
8. A spinner is made from a regular octagon. It is labelled with three $A s$, two $B s$ and three $C s$. Each of the sides is equally likely to be resting on the table when it stops spinning. Calculate :
(a) $P$ ( $A$ resting on the table)
(b) $P(B$ resting on the table)
(c) $P$ (not $C$ resting on the table)
9. A pair of die is thrown. Find the probability of getting a sum of 10 or more, if 5 appears an the first die [Hint : Favourable cases are $(5,5)$ and $(5,6)$ ]
10. A spinner is marked with numbers from 1 to 10 . What is the probability of :
(a) multiple of 3
(b) getting a prime number?
(c) not getting a multiple of 2 ?
11. In a scrabble game, there are small tiles with letters on them that are used to form words. The adjoining table shows the number of tiles for each letter. What is the probability of selecting :
(a) O from the full set?
(b) Consonant from the full set?
(c) A, M or J from the full set?
(d) Vowel from the full set?
| Letter Distribution | ||
| A - 9 B - 2 C - 2 D - 4 E - 12 F - 2 G - 3 H - 2 I - 9 | J - 1 K - 1 L - 4 M - 2 N - 6 O - 8 P - 2 Q - 1 R - 6 | S - 4 T - 6 U - 4 V - 2 W - 2 X - 1 Y - 2 Z - 1 Blank - 2 |
12.A survey of 500 families shows the following results :
| Number of girls in the family | 1 | 2 | 3 | 0 |
| Number of families | 400 | 50 | 5 | 45 |
Out of these, one is chosen at random. Find the probability that the chosen family has 2 girls.
Multiple Choice Questions (MCQs)
13. Use the spinner. Which shows the probability of spinning the letter A ?
(a) $\frac{2}{3}$
(b) $\frac{1}{3}$
(c) $\frac{2}{5}$
(d) $\frac{1}{5}$
14. A bag holds 26 tiles, each marked with a different letter. What is the probability that one tile chosen at random is not a vowel?
(a) $\frac{5}{26}$
(b) $\frac{21}{26}$
(c) $\frac{3}{13}$
(d) $\frac{1}{21}$
High Order Thinking Skills (HOTS)
15. Ankit bought 2 packs of red pens, 1 pack of blue pens, and 3 pack of black pens. The red pen packs have 4 pens each. The blue pen packs and the black pen packs have 3 pens each. He places all his pens in a pen holder. What is Ankit's probability of picking a red pen from the pen holder?
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