Question

Kyle and his brother Joel leave a rest stop at the same time traveling in opposite directions. After traveling for 6 hours, they are 780 miles apart. If Kyle drives 10 miles per hour faster than Joel, how fast was Joel traveling?

Answer 1

Joel is moving with 60 mph speed.

Explanation:

If Kyle has a speed of u mph and his brother has the speed of v mph, then as they are moving in the opposite direction, their resultant speed will be (u + v) mph.

Now, after traveling for 6 hours, they are 780 miles apart.

So,
`u + v = (780)/(6) = 130` ......... (1)

Now, if Kyle drives 10 miles per hour faster than Joel, then

u = v + 10

⇒ u - v = 10 ........ (2)

Now, solving equations (1) and (2) we get,

2u = 130 + 10 = 140

⇒ u = 70 mph

From equation (2) we have, v = u - 10 = 60 mph.

Therefore, Joel is moving with 60 mph speed. (Answer)