Answer: they would be 192 miles apart after 3 hours
Explanation:
The two trains left Metropolis at the same time.
One traveled south at 50 mph.
Distance travelled = speed × time
After 3 hours, the distance travelled by the first train southwards would be
3 × 50 = 150 miles
The other train travelled eastwards at 40 mph. After 3 hours, the distance travelled by the second train eastwards would be
3 × 40 = 120 miles
The distance between the trains at the end of 3 hours would be the hypotenuse of the triangle formed by the southward and eastward movement of both trains.
We would apply Pythagoras theorem which is expressed as
Hypotenuse² = opposite side² + adjacent side². Therefore,
Hypotenuse² = 150² + 120² = 36900
Hypotenuse = √36900 = 192 miles