A cargo plane left Los Angeles seven hours before an Air Force plane. The planes flew in opposite directions. The Air Force plane flew at 325 mph for two hours. After this time the planes were 5150 mi. apart. Find the cargo plane's speed.

speed of cargo plane = 642.857 miles per hr

Step-by-step explanation:

The planes moves in opposite direction. The cargo plane also left Los Angeles 7 hours before the Air force plane. This means the cargo plane has been travelling for 7 hrs before the Air force plane moved.

Air force plane speed = 325 miles per hr

Air force plane time = 2 hrs

speed = distance/time

distance = speed * time

distance covered = 325 * 2 = 650 miles

Cargo plane speed = ?

cargo plane time = 7 hrs

distance covered = 5150 - 650 = 4500 mile

speed = distance/time

speed = 4500/7

speed of cargo plane = 642.857 miles per hr