A hiker walks three sections of a trail that are of equal length. The

Isn't pace the inverse of speed? Bunuel

I'm a bit confused.
The question says the speed has doubled in the third section.

So, shouldn't this mean that the speed = 3*2 = 6mph??
Why did we double the speed of his uphill task??? It wasn't clearly mentioned was it?

Would appreciate an explanation.

Thanks!

Speed calculation is is wrong for 3rd trail.

I think the same. It isn't clear enough.

Confused with speed calculation in third trail

if its not mentioned that his speed in the first section doubled, then we will have to consider the present speed . which is the speed in 2nd second. because "his speed" means speed at which he is currently travelling in.

I believe that the blue portion below reflects the intent of the problem-writer:



Total distance of the 3-section trail = 3 * (rate for the first section * time for the first section) = 3 * (3*1.5) = 13.5 miles

Rate and time have a RECIPROCAL RELATIONSHIP.

Since the rate for the second section is 3/4 the rate for the first section, the time for the second section is 4/3 the time for the first section:
4/3 * 3/2 = 2 hours

Since the rate for the third section is 2 times the rate for the second section, the time for the third section is 1/2 the time for the second section:
1/2 * 2 = 1 hour

Average speed \(= \frac{total-distance}{total-time} = \frac{13.5}{1.5+2+1} = \frac{13.5}{4.5} = 3\) miles per hour

Given: A hiker walks three sections of a trail that are of equal length. The first section of the trail is flat, and on this section the hiker travels at 3 miles per hour for 1.5 hours. The second section is uphill, and on this section the hiker’s pace slows by 25 percent. The third section is downhill, and here his speed doubles.

Asked: What was the hiker’s average speed for the entire three-section hike?

Total distance = 3*3*1.5 = 13.5 miles
Total time = 1.5 + 1.5/.75 + 1.5/2*.75 = 1.5 + 2 + 1 = 4.5 hours
Average speed = 13.5 /4.5 miles/hour = 3 miles/hour

IMO B