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An aeroplane travels a distance in the form of a square with the speed of 400 km per hr, 600 km per hr, 800 km per hr. and 1200 km per hr respectively. Find the average speed for the whole distance along the four sides of the square.
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- 640 kmph
- 620 kmph
- 630 kmph
- 650 kmph
Correct Option: A
As distance is covered along four sides (equal) of a square at different speeds, the average speed of the aeroplane
| = | |||||||||
| + | + | + | |||||||
| 400 | 600 | 800 | 1200 | ||||||
[∵ All the sides of square are equal, so distance between them is same]
| = | |||||
| 12000 | |||||
| = | = 640 km per hr. | |
| 75 |
