Question 243576
D=RT
D=(X+5)*2
D=(X-5)*4
(X+5)*2=(X-5)*4
2X+10=4X-20
2X-4X=-20-10
-2X=-30
X=-30/-2
X=15 MPH IS THE SPEED OF THE BOAT IN STILL WATER.
PROOF:
(15+5)*2=(15-5)*4
20*2=10*4
40=40