The distance from Pier A to Pier B can be determine by using speed formula.
The distance from Pier A to Pier B is \(15\:\rm miles\).
Given:
The time to reach from Pier A to Pier B is 2 hour.
The time took in return is \(6 \:\rm hour\).
The speed is \(2.5\:\rm mph\).
Write the speed formula.
\(v=\dfrac{d}{t}\)
Where, \(v\) is velocity, \(t\) is time and \(d\) is distance.
\(d=vt\)
When boat go pier A to B with the current of 2.5 mph.
\(d=(v+2.5)\times 2\\d=2v + 5\)
Calculate distance return time.
\(d = ( v - 2.5)\times 6\\d = (6v - 15)\)
The above equation we can write as,
\(2v+5=6v-15\\20=4v\\v=5\:\rm mph\)
Now, the substitute the value of \(v\).
\(d = 2v + 5\\d = 2(5) + 5\\d = 15\:\rm miles\)
Thus, the distance from Pier A to Pier B is \(15\:\rm miles\).
Learn more about speed and time here:
https://brainly.com/question/10206512
