Question

starting at home, Omar traveled uphill to the gift store for 30 minutes at just 10mph. He then travelled back home along the same path downhill at a speed of 30mph. What is his average speed for the entire trip to the gift store and back?

Answer 1

Answer:

average speed for the entire trip is 15 mph

Step-by-step explanation:

Let x be the uphill speed and y be the downhill speed.

We have been given that

Speed of Omar in uphill to reach gift store = x =10 mph

Speed of Omar in downhill to reach his home = y = 30 mph

We know the formula for average speed for the entire trip

$\text{Average speed }=\frac{2xy}{x+y}\\\\=\frac{2\times 10\times 30}{10+30}\\\\=\frac{600}{40}\\\\=15$

Therefore, average speed is 15 mph

Answer 2

We know, Speed = Distance / time
Let, the distance = d
Time for first trip = d/10
Time for second trip = d/30

Total time = d/10 + d/30 = 4d/30

Now, Average speed = total distance / total time
s = 2d / 4d / 30
s = 2d*30 / 4d
s = 30/2
s = 15

In short, Your Answer would be: 15 mph

Hope this helps!