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- 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 banker's gain on a certain sum due 1 1 years hence is 3 of the banker's 2 25 discount. The rate percent is:
Options- A.
5 1 % 5 - B.
9 1 % 11 - C.
8 1 % 8 - D.
6 1 % 6
Discuss
- 2. If two marbles are picked at random, what is the probability that both marbles are red?
Options- A. 1/6
- B. 1/3
- C. 2/15
- D. None of the above Discuss
- 3. A and B together have Rs. 1210. If 4⁄15 of A's amount is equal to ⅖ of B's amount, how much amount does B have?
Options- A. Rs. 460
- B. Rs. 484
- C. Rs. 550
- D. Rs. 664 Discuss
- 4. Three taps A, B and C fill a tank in 20 min, 15 min and 12 min, respectively. If all the taps are opened simultaneously, how long will they take to fill 40% of the tank?
Options- A. 1 min
- B. 2 min
- C. 3 min
- D. 4 min Discuss
- 5. When 0.252525...........is converted into a fraction, then find the result.
Options- A. 25/99
- B. 25/90
- C. 25/999
- D. 25/9999 Discuss
- 6. The sides of a triangle area in the ratio of 1/3 : 1/4 : 1/5 and its perimeter is 94 cm.
Find the length of the smallest side of the triangle .
Options- A. 18 cm
- B. 22.5 cm
- C. 24 cm
- D. 27 cm Discuss
- 7. The salary of A, B, C, D, E is Rs. 8000, Rs. 5000, Rs. 11000, Rs. 7000, Rs. 9000 per month respectively, then the average salary of A, B, C, D, and E per month is
Options- A. Rs. 7000
- B. Rs. 8000
- C. Rs. 8500
- D. Rs. 9000 Discuss
- 8. The sum of the squares of three numbers is 138, while the sum of their products taken two at a time is 131. Their sum is:
Options- A. 20
- B. 30
- C. 40
- D. None of these Discuss
- 9. Neeta borrowed some money at the rate of 6% per annum for the first 3 yr. at the rate of 9% per annum for the next 5 yr and a the rate of 13% per annum for the period beyond 8 yr. If she pays a total interest of ? 8160 at the and of 11 yr how much money did she borrow?
Options- A. ? 12000
- B. ? 10000
- C. ? 8000
- D. Data is inadequate Discuss
- 10. Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:
Options- A. 50 m
- B. 72 m
- C. 80 m
- D. 82 m Discuss
More questions
Correct Answer:
| 9 | 1 | % |
| 11 |
Explanation:
| Then, B.G. = Re. | 3 | . |
| 25 |
| ∴ T.D. = (B.D. - B.G.) = Re. | ❨ | 1 - | 3 | ❩ | = Re. | 22 | . |
| 25 | 25 |
| Sum = | ❨ | 1 x (22/25) | ❩ | = Rs. | 22 | . |
| 1-(22/25) | 3 |
| S.I. on Rs. | 22 | for 1 | 1 | years is Re. 1. |
| 3 | 2 |
| ∴ Rate = | ❨ | 100 x 1 | ❩% |
|
|||||||
|
Correct Answer: None of the above
Explanation:
Total number of marbles = 6 + 4 + 2 + 3 = 15
Ways of selection of two red marbles = n(E) = 6C2
Ways of selection of two marbles = n(S) = 15C2
So, required probability = (6C2) / (15C2)
= (6 x 5) / (15 x 14) = 1/7
Correct Answer: Rs. 484
Explanation:
| 4 | A | = | 2 | B | |
| 15 | 5 |
| ⟹ A = | ❨ | 2 | x | 15 | ❩B |
| 5 | 4 |
| ⟹ A = | 3 | B |
| 2 |
| ⟹ | A | = | 3 |
| B | 2 |
⟹ A : B = 3 : 2.
| ∴ B's share = Rs. | ❨ | 1210 x | 2 | ❩ | = Rs. 484. |
| 5 |
Correct Answer: 2 min
Explanation:
Part of the tank filled in 1 min by A, B and C = 1/20 + 1/15 +1/12
= (3 + 4 + 5)/60 = 12/60 = 1/5
? Time taken by A, B and C to fill the tank = 5 min
? Time taken by A, B and C to fill 40% of the tank = 40% of 5 = (40/100) x 5 = 2 min.
Correct Answer: 25/99
Explanation:
0.252525 ..... = 0.25= 25/99
Correct Answer: 24 cm
Explanation:
Given ratio = 1/3 : 1/4 : 1/5 = 20 : 15 : 12
Let length of the sides be 20k, 15k and 12k.
Then, according to the question,
20k + 15k + 12k = 94
? 47k = 94
? k = 94/47 = 2
Smallest side = 12k = 12 x 2 = 24 cm
Correct Answer: Rs. 8000
Explanation:
Average salary
= 8000 + 5000 + 11000 + 7000 + 9000 / 5
= Rs. 8000
Correct Answer: 20
Explanation:
Then, a2 + b2 + c2 = 138 and (ab + bc + ca) = 131.
(a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca) = 138 + 2 x 131 = 400.
⟹ (a + b + c) = √400 = 20.
Correct Answer: ? 8000
Explanation:
Let the sum borrowed = P
Then, according to the question,
[(P x 6 x 3)/100] + [(P x 9 x 5)/100] + [(P x 13 x 3)/100] = 8160
? (18P + 45P +39P) / 100 = 8160
? 102P/100 = 8160
? P = (8160 x 100)/102
? P = ? 8000
Correct Answer: 50 m
Explanation:
Let the length of each train be x metres.
Then, distance covered = 2x metres.
Relative speed = (46 - 36) km/hr
| = | ❨ | 10 x | 5 | ❩m/sec |
| 18 |
| = | ❨ | 25 | ❩m/sec |
| 9 |
| ∴ | 2x | = | 25 |
| 36 | 9 |
⟹ 2x = 100
⟹ x = 50.
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