Quantitative Aptitude Ques 1038
Question: A plane left 30 min later than the scheduled time and in order to reach the destination 1500 km away in time, it had to increase the speed by 250 km/h from the usual speed. Its usual speed is [NICL and GIC (AO) 2013]
Options:
A) 720 km/h
B) 730 km/h
C) 740 km/h
D) 750 km/h
E) None of the above
Show Answer
Answer:
Correct Answer: D
Solution:
- Usual speed of plane $ =xkm/h $
$ \therefore $ New speed $ =(x+250),km/h $
$ \therefore $ $ \frac{1500}{x}-\frac{1500}{x+250}=\frac{30}{60} $
$ \Rightarrow $ $ 1500( \frac{x+250-x}{x(x+250)} )=\frac{1}{2} $
$ \Rightarrow $ $ x(x+250)=1500\times 500=750000 $
$ \Rightarrow $ $ x(x+250)=750(750+250) $
$ \Rightarrow $ $ x=750km/h $
BETA
