Question

Two trains travel at right angles to each other after leaving the same train station at the same time. Two hours later they are 65.30 miles apart. If one travels 14 miles per hour slower than the other, what is the rate of the slower train? (Round your answer to the nearest integer)

Answer 1

Answer:

15 miles per hour is the speed of the slower train.

Step-by-step explanation:

As given in the figure attached,

Let the speed of train 1 is v and train 2 is u.

Therefore, distance traveled in 2 hours by train 1 will be = 2v miles

and distance traveled by train 2 will be = 2u miles

Now we can see in the figure a right angle triangle is formed by the two trains.

AB² + BC² = AC²

(2v)² + (2u)²= (65.30)²

4v² + 4u² = 4264.09

Now we divide this equation by 4

v² + u² = 1066.02

If speed of the slower train is v miles per hour then as per statement of the question.

u = v - 14

v = u + 14

By putting the value of v in the equation

(u + 14)² + u² = 1066

u² + 196 + 28u + u² = 1066

2u² + 28u + 196 = 1066

2u² + 28u + 196 - 1066 = 0

2u² + 28u - 870 = 0

By diving this equation by 2

u² + 14u - 435 = 0

u² + 29u - 15u - 435 = 0

u(u + 29) - 15(u + 29) = 0

(u + 29)(u - 15) = 0

u = -29, 15

Since speed can not be with negative notation so u = 15 miles per hour will be the speed.

Therefore, 15 miles per hour is the speed of the slower train.