Cargo ship

Hi cheater. I want to first say you did a much better job of disguising your cheating today. Kudos.

Let M be the position of the ship at the moment the missile is fired. Let V be the point a quarter of the way around the circle from M (in the direction the ship is moving).Take the point at which Lighthouse is situated to be U. Then the missile moves along the semi-circle on diameter UV and hits the ship at V.

To see this take a point T on the quarter circle and let the line UT meet the semi-circle at R. Let Z be the center of the semicircle. The angle VZR is twice the angle VUR, so the arc VT is the same length as the arc VR. Hence also the arc UR is the same length as the arc MT. So time needed= 10 *pi*3600 /1500 =75.43

Hence, choice (3) is the right answer

shashank.ism wrote:A cargo ship circles a lighthouse at a distance 20 km with speed 1500 km/h. A torpedo launcher fires a missile towards the ship from the lighthouse at the same speed and which moves so that it is always on the line between the lighthouse and the ship. How long does it take to hit?

A) 37.7 secs
B) 56.57 secs
C) 75.43 secs
D) 94.29 secs
E) 113.14 secs

Your game has been exposed. You are copying and pasting solutions directly from another site. You should be eliminated along with your co conspirator.