A plan left 40 minutes late due to bad whether and order to reach its destination 1600 km away in time, it had increase its speed by 400 kmph from its usual speed. Find the usual speed of the plane?
A. 600 km/hour
B. 400 km/hour
C. 1000 km/hour
D. 800 km/hour
Answer: Option D
Solution(By Examveda Team)
Let usual speed be X kmph, then new speed will be (x + 400) kmph. Time taken to cover 1600 km with speed X kmph, = $$\frac{{1600}}{{\text{x}}}$$ Time taken to cover 1600 km with Speed (x + 400) kmph, = $$\frac{{1600}}{{{\text{x}} + 400}}$$ Now, Time difference = 40 minutes. $$\frac{{1600}}{{\text{x}}} - \frac{{1600}}{{{\text{x}} + 400}} = \frac{{40}}{{60}}$$ hours x2 + 400x - 960000 = 0 On solving, x = -1200, 800 Speed cannot be negative, So usual speed will be 800 km/hourRelated Questions on Speed Time and Distance
A. 48 min.
B. 60 min.
C. 42 min.
D. 62 min.
E. 66 min.
A. 262.4 km
B. 260 km
C. 283.33 km
D. 275 km
E. None of these
A. 4 hours
B. 4 hours 30 min.
C. 4 hours 45 min.
D. 5 hours
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