Question 683004
Let distance be x

upstream speed = 15-3=12 mi/h
downstream speed = 15+3=18 mi/h

Time upstream + time downstream = 25 minutes= 25/60 = 5/12 hours

t=d/r
x/12 + x/18 = 5/12

LCD = 36
multiply equation by 36

3x+2x=15
5x=15
x=3 miles