Question

Plane 1 leaves city A at 7 am and flies at a speed of 250 mph in a straight line towards city B, located 1000 miles North of city A. Plane 2 leaves city C located 300 miles East and 400 miles North of city A at 7:30 am and flies West at a speed v mph. The planes fly at the same altitude. For which value of v do they collide ?

Answer 1

Answer:v=142.85 mph

Explanation:

Given

Distance between two cities is 1000 miles

Speed of plane 1 id 250 mph

Plane 1 leaves at 7 am and Plane 2 leaves at 7:30 am

They will collide if plane 2 travels 300 miles and Plane  1 travels 400 miles in t and t+0.5 hr  respectively

Time taken by plane 2

$t=\frac{300}{v}$----1

time taken by plane  1 to travel 400 miles

$t+0.5=\frac{400}{250}$-----2

substitute value of t in 2

$\frac{300}{v}+0.5=\frac{400}{250}$

$\frac{300}{v}=2.1$

$v=\frac{300}{2.1}=142.85 mph$