Question

an aeroplane with a speed of 600 km/h in still air requires 22.5 minutes longer to fly from a to b against 40 km/h wind than from b to a with the wind. Find the distance between a and b.

Answer 1

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2. A person crosses a 600 m long street in 5 minutes. What is his speed in km per hour?A. 8.2B. 4.2C. 6.1D. 7.2View Answer|Notebook| Discuss

3. Excluding stoppages, the speed of a bus is 54 kmph and including stoppages, it is 45 kmph. For how many minutes does the bus stop per hour?A. 12B. 11C. 10D. 9View Answer|Notebook| Discuss

4. A man complete a journey in 10 hours. He travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km.A. 121 kmB. 242 kmC. 224 kmD. 112 kmView Answer|Notebook| Discuss

5. A car traveling with 5/7 of its actual speed covers 42 km in 1 hr 40 min 48 sec. What is the actual speed of the car?A. 30 km/hrB. 35 km/hrC. 25 km/hrD. 40 km/hrView Answer|Notebook| Discuss

6. A man covered a certain distance at some speed. If he had moved 3 kmph faster, he would have taken 40 minutes less. If he had moved 2 kmph slower, he would have taken 40 minutes more. What is the the distance in km?A. 36B. 38C. 40D. 42View Answer|Notebook| Discuss

Answer 2

Answer:

• The distance between A and B = 1680 km

Step-by-step explanation :

Given :

• Speed of aeroplane = 600 km/h

• Required time = 22½ minutes longer to fly A to B.

To find :

The distance from A to B =?

Let the distance between A and B be x km.

The ground speed of the aeroplane flying at 600 km/h against the wind blowing at 40 km/hr is (600 - 40) km/hr i.e. 560 km/hr. Similarly, the ground speed of the aeroplane with the wind is (600 + 40) km/hr i.e. 640 km/h.

The time of flight of the aeroplane from A to B =x/560 hr

and the time of flight of the aeroplane from B to A =x/640 hr.

According to the problem,

⟹ x/ 560 = x/640 + 3/8 [ ∵ 22½ minutes = (45/2 ×1/60) hr = 3/8 hr]

⟹ 8x = 7x + 1680 (Multiplying both sides by 4480)

⟹ 8x - 7x = 1680

⟹ x = 1680.

The distance between A and B = 1680 km.