AAPL wrote:Official Guide



In the figure above, \(V\) represents an observation point at one end of a pool. From \(V\), an object that is actually located on the bottom of the pool at point \(R\) appears to be at point \(S\). If \(VR=10\) feet, what is the distance \(RS\), in feet, between the actual position and the perceived position of the object?

A. \(10-5\sqrt{3}\)
B. \(10-5\sqrt{2}\)
C. \(2\)
D. \(2\frac{1}{2}\)
E. \(4\)

OA A

Say the perpendicular dropped from point V to the extended line RS is O; thus, OV and RS are perpendicular to each other.

Thus, ∆OVR is a right-angled triangle. And, OR^2 = VR^2 - OV^2 = 10^2 - 5^2 = √75

=> OR = 5√3

Thus, RS = OS - OR = 10 - 5√3

The correct answer: A

Hope this helps!

-Jay
_________________
Manhattan Review GMAT Prep

Locations: GMAT Classes Boston | GMAT Tutoring NYC | GRE Prep Dallas | TOEFL Prep Classes Seattle | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.