Discussion
Home ‣ Aptitude ‣ Probability See What Others Are Saying!
- Question
In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:
Options- A. 21/46
- B. 1/5
- C. 3/25
- D. 1/50
- Correct Answer
- 21/46
ExplanationLet S be the sample space and E be the event of selecting 1 girl and 2 boys.
Then, n(S) = Number ways of selecting 3 students out of 25
= = 2300.
n(E)= = 1050.
P(E) = n(E)/n(s) = 1050/2300 = 21/46
- 1. The smallest positive prime (say p) such that 2 p - 1is not a prime is
Options- A. 5
- B. 11
- C. 17
- D. 29 Discuss
- 2. 16, 25, 36, 72, 144, 196, 225
Options- A. 36
- B. 72
- C. 196
- D. 225 Discuss
- 3. 8, 13, 21, 32, 47, 63, 83
Options- A. 47
- B. 63
- C. 32
- D. 83 Discuss
- 4. [( 3.242 x 14 ) / 100] =?
Options- A. 0.045388
- B. 4.5388
- C. 453.88
- D. None of these Discuss
- 5. From a point P on a level ground, the angle of elevation of the top of a tower is 30°, if the tower is 100 m high, find the distance of point P from the foot of the tower.
Options- A. 100 m
- B. 173 m
- C. 200 m
- D. 273 m Discuss
- 6. Ayesha's father was 38 years of age when she was born while her mother was 36 years old when her brother four years younger to her was born. What is the difference between the ages of her parents?
Options- A. 2 years
- B. 4 years
- C. 6 years
- D. 8 years Discuss
- 7. A dishonest milkman professes to sell his milk at cost price but he mixes it with water and thereby gains 25%. The percentage of water in the mixture is:
Options- A. 4%
- B. 6¼%
- C. 20%
- D. 25% Discuss
- 8. A farmer travelled a distance of 61 km in 9 hours. He travelled partly on foot @ 4 km/hr and partly on bicycle @ 9 km/hr. The distance travelled on foot is:
Options- A. 14 km
- B. 15 km
- C. 16 km
- D. 17 km Discuss
- 9. 3.2 x 8.1 + 3185 ÷ 4.95 =?
Options- A. 670
- B. 660
- C. 645
- D. 690 Discuss
- 10. Exp. = (.35 x .0015) / (.25 x .07) written as a percentage is?
Options- A. 0.3 %
- B. 3 %
- C. 30 %
- D. None of these Discuss
More questions
Correct Answer: 11
Explanation:
Taking p = 11
2p - 1 = 211 - 1
= 2047
Since 2047 is divisible by 23 it is not prime. Thus, required least positive prime number is 11.
Correct Answer: 72
Explanation:
Correct Answer: 47
Explanation:
So, the number 47 is wrong and must be replaced by 46.
Correct Answer: 0.045388
Explanation:
Multiplying 3.242 x 14=4.5388
Now divide 4.5388 by 100
So, 4.5388 ÷ 100= 0.045388
? Shift the decimal two places to the left as 100
Correct Answer: 173 m
Explanation:
Let us draw a figure from given question.
Let, AB = 100 m be the height of a tower, P is a point on the ground such that ∠APB = 30°
From right triangle ABP,
BP = 100 cot 30°
⇒ BP = 100 √3
⇒ BP = 100 X 1.73
⇒ BP = 173 meter
Correct Answer: 6 years
Explanation:
Father's age when Ayesha's brother was born = (38 + 4) years = 42 years.
∴ Required difference = (42 - 36) years = 6 years.
Correct Answer: 20%
Explanation:
Then, S.P. of 1 litre of mixture = Re. 1, Gain = 25%.
| C.P. of 1 litre mixture = Re. | ❨ | 100 | x 1 | ❩ | = | 4 |
| 125 | 5 |
By the rule of alligation, we have:
| C.P. of 1 litre of milk C.P. of 1 litre of water | |||||
| Re. 1 | Mean Price
|
0 | |||
|
|
||||
| ∴ Ratio of milk to water = | 4 | : | 1 | = 4 : 1. |
| 5 | 5 |
| Hence, percentage of water in the mixture = | ❨ | 1 | x 100 | ❩% | = 20%. |
| 5 |
Correct Answer: 16 km
Explanation:
Then, distance travelled on bicycle = (61 -x) km.
| So, | x | + | (61 -x) | = 9 |
| 4 | 9 |
⟹ 9x + 4(61 -x) = 9 x 36
⟹ 5x = 80
⟹ x = 16 km.
Correct Answer: 670
Explanation:
? = 3.2 x 8.1 + 3185 ÷ 4.95
= 25.92 + 643.43 = 669.35 = 670
Correct Answer: 3 %
Explanation:
Exp. = (.35 x .0015) / (.25 x .07)
= ( 35 x 15) / (25 x 7 x 100)
= (3/100) x 100 %
= 3%
Comments
There are no comments.More in Aptitude:
Programming
Copyright ©CuriousTab. All rights reserved.