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- Question
A train overtakes two persons walking along a railway track. The first one walks at 4.5 km/hr. The other one walks at 5.4 km/hr. The train needs 8.4 and 8.5 seconds respectively to overtake them. What is the speed of the train if both the persons are walking in the same direction as the train?
Options- A. 66 km/hr
- B. 72 km/hr
- C. 78 km/hr
- D. 81 km/hr
- Correct Answer
- 81 km/hr
Explanation4.5 km/hr = ❨ 4.5 x 5 ❩ m/sec = 5 m/sec = 1.25 m/sec, and 18 4 5.4 km/hr = ❨ 5.4 x 5 ❩ m/sec = 3 m/sec = 1.5 m/sec. 18 2 Let the speed of the train be x m/sec.
Then, (x - 1.25) x 8.4 = (x - 1.5) x 8.5
⟹ 8.4x - 10.5 = 8.5x - 12.75
⟹ 0.1x = 2.25
⟹ x = 22.5
∴ Speed of the train = ❨ 22.5 x 18 ❩ km/hr = 81 km/hr. 5 - 1. A can complete a piece of work in 10 days, while B alone can complete it in 15 days. They work together for 5 days and rest of the work is done by C in 2 days. If they receive $ 450 for the whole work, how should they divide the money?
Options- A. $250, $100, $100
- B. $225, $150, $75
- C. $200, $150, $100
- D. $175, $175, $100 Discuss
- 2. The angle of elevation of a tower from a distance 50 m from its foot is 30°. The height of the tower is :
Options- A. 50 ?3 m
- B. 50 m ?3
- C. 75 ?3 m
- D. 75 m ?3 Discuss
- 3. If 30% of A = 20 % of B, then find the value of A : B?
Options- A. 1 : 3
- B. 3 : 2
- C. 3 : 1
- D. 2 : 3 Discuss
- 4. 80 litre mixture of milk and water contains 10% milk. How much milk (in litres) must be added to make water percentage in the mixture as 80%?
Options- A. 8
- B. 9
- C. 10
- D. 12 Discuss
- 5. If log 5 (x 2 + x) - log 5 x = 2 then the value of x is?
Options- A. 24
- B. 25
- C. 23
- D. 120 Discuss
- 6. The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?
Options- A. 0
- B. 1
- C. 10
- D. 19 Discuss
- 7. Two trains A and B travel from points X to Y and the ratio of the speeds of A to that of B is 2 : 7. Find the ratio of time taken by A and B to reach From X to Y.
Options- A. 2 : 5
- B. 3 : 5
- C. 3 : 8
- D. 7 : 2 Discuss
- 8. Walking with 3/4 of his usual speed, Sachin covers a certain distance in 2 h more than the time he takes to cover the distance at his usual speed. Find the time taken by him to cover this distance with usual speed.
Options- A. 5 h
- B. 6 h
- C. 9 h
- D. 4 h Discuss
- 9. If ? 2 n = 64, then the value of n is?
Options- A. 2
- B. 4
- C. 6
- D. 12 Discuss
- 10. Ram and Sita are walking towards each other with the speed of 8 km/h and 2 km/h, respectively over a road 160 km long. How soon will they meet?
Options- A. 16 h
- B. 8 h
- C. 10 h
- D. 20 h Discuss
More questions
Correct Answer: $225, $150, $75
Explanation:
Correct Answer: 50 m ?3
Explanation:
Correct Answer: 2 : 3
Explanation:
Given that, 30 % of A = 20 % of B
? A/B = 20/30 = 2/3
? A : B = 2 : 3
Correct Answer: 10
Explanation:
Let initial quantity be Q, and final quantity be F
F = Q(1 - 8/Q)
=> Q = 20
Correct Answer: 24
Explanation:
? log5[(x2 + x ) / x] = 2
? log10(x + 1) = 2
? x + 1 = 25
? x = 24
Correct Answer: 19
Explanation:
Average of 20 numbers = 0.
∴ Sum of 20 numbers (0 x 20) = 0.
It is quite possible that 19 of these numbers may be positive and if their sum is a then 20th number is (-a).
Correct Answer: 7 : 2
Explanation:
We know that speed is inversely proportional to time.
Given that, (Speed of A ) : (speed of B ) = 2 : 7
?(Time taken by A ) : (Time taken by B ) = 1/2 : 1/7 = 7 : 2
Correct Answer: 6 h
Explanation:
Let th distance = D
and usual speed = V
According to the question,
D/(3V/4) - D/V = 2
? D/V = 3 x 2 = 6
Time taken to cover the distance with usual speed = 6 h
Correct Answer: 12
Explanation:
?2n = 64
? 2n/2 = 26
? n/2 = 6
? n = 12
Correct Answer: 16 h
Explanation:
Distance = 160 km
Relative Speed = 8 + 2 = 10
Time = Distance/Relative speed = 160/10 = 16 h
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