Question 29569
Let the speed of the current be x

9 minutes = 0.15hours
15 minutes = 0.25 hors
EquatioN:


<font color = green>0.15(16+x)=0.25(15-x)</font>
2.4+0.15x=4-0.25x
-1.6=-0.4x
x=4


<font color = grey> Hence, the speed of the current is 4mph.</font>
Paul.