Question

Bob is hiking down a 15-mile country trail. He could hike at 5 mph for the first 2 hours and then go the rest of the way at 3 mph or he could just go the whole way at 4 mph. How long would each of these options take?

Answer 1

1) 11/3 hours or about 3.67 hours.

2) 3.75 hours.

Step-by-step explanation:

Let’s determine the time it will take for Bob to hike for each of the options.

Option 1) Hiking 5mph for 2 hours, then 3mph.

The total distance is 15 miles.

If Bob hiked 5mph for 2 hours, then after two hours, Bob would’ve covered 5(2)=10 miles out of 15.

Therefore, 15-10 or 5 miles still needs to be covered.

To find how long that will take, we can simply divide the distance by the rate.

We are now going at a rate of 3mph. So, 5/3 is about 1.67 hours.

So, it will take another 1.67 hours to complete the hike.

So, the total time it will take is 2+1.67 or abou 3.67 hours. More specifically, it will be 2+5/3 or 11/3 hours.

Option 2) Hiking 4mph the entire way.

The total distance is 15 miles.

If Bob hiked 4mph the entire way, to find how long it will take, we can simply divide the total distance by the rate.

So: 15/4=3.75.

Therefore, it will take 3.75 hours to hike the entire distance going 4mph.

Explanation:

Answer 2

1) 11/3 hours or about 3.67 hours.

2) 3.75 hours.

Explanation:

Let’s determine the time it will take for Bob to hike for each of the options.

Option 1) Hiking 5mph for 2 hours, then 3mph.

The total distance is 15 miles.

If Bob hiked 5mph for 2 hours, then after two hours, Bob would’ve covered 5(2)=10 miles out of 15.

Therefore, 15-10 or 5 miles still needs to be covered.

To find how long that will take, we can simply divide the distance by the rate.

We are now going at a rate of 3mph. So, 5/3 is about 1.67 hours.

So, it will take another 1.67 hours to complete the hike.

So, the total time it will take is 2+1.67 or abou 3.67 hours. More specifically, it will be 2+5/3 or 11/3 hours.

Option 2) Hiking 4mph the entire way.

The total distance is 15 miles.

If Bob hiked 4mph the entire way, to find how long it will take, we can simply divide the total distance by the rate.

So: 15/4=3.75.

Therefore, it will take 3.75 hours to hike the entire distance going 4mph.