Nafi can row down a 20- mile stream in 2 hours and can return in upstream in 5 hours.What is his average rate,in miles per hour,for the entire trip?
a.10/7
b.7/2
c.20/6
d.3
e.40/7
avg rate = (total distance)/(total time) = (20+20)/(2+5) = ?
To find the average rate for the entire trip, we need to calculate the total distance traveled and the total time taken.
Let's start by calculating the total distance. Nafi rows down the stream for 20 miles and then rows back upstream for another 20 miles. So the total distance is 20 + 20 = 40 miles.
Next, let's calculate the total time taken. Nafi takes 2 hours to row down the stream and 5 hours to row back upstream. So the total time taken is 2 + 5 = 7 hours.
To find the average rate, we divide the total distance by the total time: 40 miles / 7 hours.
Simplifying the fraction, we get:
40/7 miles per hour.
Therefore, the average rate for the entire trip is 40/7 miles per hour.
The correct option is e. 40/7.
To find Nafi's average rate for the entire trip, we need to calculate the total distance traveled and the total time taken.
Let's start by calculating the total distance traveled. We know that the stream is 20 miles long, and Nafi rows down the stream and then returns upstream. Therefore, the total distance traveled is twice the length of the stream, which is 2 * 20 = 40 miles.
Next, let's calculate the total time taken. We are given that Nafi takes 2 hours to row down the stream and 5 hours to row upstream. So the total time taken is 2 + 5 = 7 hours.
Now, we can find Nafi's average rate by dividing the total distance traveled by the total time taken:
Average rate = total distance / total time
Average rate = 40 miles / 7 hours
To simplify the fraction, we can express it in simplest form:
Average rate = 40/7
The answer is therefore:
e. 40/7
So, Nafi's average rate for the entire trip is 40/7 miles per hour.