60 miles per hour. In two miles the sum of the distance the two trains traveled was 200 miles, you divide that by 2, the sum of the speed of the two trains is 100 miles per hour, now put the speed of the slow train as x and the fast as x +20, the sum of x and x +20 is 100, so 2x + 20 =100, you subtract 20 from both sides, 2x = 80, divide by 2, x = 40, the problem asks for the speed of the fast train, so, x + 20 is 60.
Here you would want to use the sine function, since it’s making a triangle with the ground, and length of the string, the height to the kite. This can be found by 65sin(70°) which is ≈ 61.08 meters
