Answer:
We know that the equation for the speed is:
Speed = Distance/time.
First, we know that he walks 2 miles in 15 minutes.
distance = 2miles
time = 15 minutes
Then his speed in that interval is:
Speed = (2 mi)/(15 min) = (2/15) miles per minute.
Now, at this same speed, he wants to walk 3 more miles. And we want to find the equation that represents how much time she needs to walk 5 miles (the 2 first miles plus the other 3 miles)
We use again the equation:
Speed = Distance/Time
But we isolate Time, to get:
Time = Distance/Speed
Where:
Distance = 5 miles
Speed = (2/15) miles per min
Time = (5 miles)/((2/15) miles per min) = 37.5 minutes
She needs 37.5 minutes to walk the 5 miles.
