CEE Kerala Engineering
CEE Kerala Engineering Solved Paper-2010
question_answer
An aeroplane flies around a square field ABCD of each side 1000 km. Its speed along AB is \[250\text{ }km{{h}^{-1}},\]along BC\[500\text{ }km{{h}^{-1}},\] along CD \[200km{{h}^{-1}},\]and along DA \[100\text{ }km{{h}^{-1}}\]. Its average speed (in\[km{{h}^{-1}}\])over the entire trip is
A) 225.5
B) 175.5
C) 125.5
D) 310.5
E) 190.5
Correct Answer:
E
Solution :
Time along the \[AB=\frac{1000}{250}=4\text{ }h\] Time along the \[BC=\frac{1000}{500}=2\text{ }h\] Time along the\[CD=\frac{1000}{200}=5\text{ }h\] Time along the \[AD=\frac{1000}{100}=10\text{ }h\] Average speed \[=\frac{Total\,dis\tan ce}{Total\,time}\] \[=\frac{4\times 1000}{4+2+5+10}=\frac{4000}{21}\] \[=190.5\text{ }km/h\]