Sagot :
Answer:= 20 MPH
Step-by-step explanation:
LET THE SPEED IN STILL WATER BE X MPH
UPSTREAM SPEED = X- 4 MPH
DOWNSTREAM SPEED = X+4 MPH
SINCE DISTANCE COVERED IS SAME BOTH WAYS
3 (X-4) = 2 (X+4)
3X - 12 = 2X+8
X= 20 MPH ANSWER
CHECK
2 X (20 +4) = 48 MILES
3 X (20–4) = 48 MILES
SHORT CUT
SPEED OF BOAT = Y (T2 +T1) / (T2 - T1)
Y = STREAM SPEED , T2 = UPSTREAM TIME , T1 = DOWNSTREAM TIME
= 4 (5) (1) = 20 MPH ANSWER