Was Rylon’s average speed greater than 55 miles per hour? (1) Rylon dr

The answer is (D). We need to know whether the average speed is over 50 mph. Therefore, we will work with the average speed formula, of which we have 2. When we just have the distance and time, we work with the \(\frac{total distance}{total time}\) formula. But when we have distance and speed, we can calculate the time and then work out the average speed.

Lets get to the good stuff now.

Statement (1) states that Rylon drove 100 miles in 1 hr 48 mins. Speed = \(\frac{distance}{time}\)
=> Speed = \(100/1\frac{48}{60}\)
=> 100/1.8=55.5555. Therefore, statement (1) is sufficient.

Statement (2) states that Rylon drove 60 miles at 60mph and 40 miles at 50mph. We can use a weighted average here or we can do a manual calculation of distance travelled in time. I prefer the following calculation.
=> travelling 60 miles at 60 mph will take 1 hour. Travelling 40 miles at 50 mph will take 4/5th of an hour (40/50) so 60 * \frac{4}{5} is 48 minutes.
Thus, 1 hour + 48 minutes to travel a distance of 60 miles + 40 miles. Thats 1 hr 48 mins to travel 100 miles. Plug this into our first formula and we get the average speed.
Therefore, statement (2) is sufficient as well.

Thus, the correct answer is option (D).