Q. A boat can cover a distance of 48 km downstream in 4 hours. If the speed of the stream is 4 km/h, what is the speed of the boat in still water?
A.8 km/h
B.10 km/h
C.12 km/h
D.14 km/h
Solution
Let the speed of the boat in still water be y km/h. Downstream speed = y + 4 km/h. Therefore, (y + 4) * 4 = 48. Solving gives y = 12 km/h.
Correct Answer: C — 12 km/h
Q. A boat can go 10 km/h in still water. If the speed of the current is 2 km/h, how long will it take to travel 50 km downstream?
A.2 hours
B.3 hours
C.4 hours
D.5 hours
Solution
Speed downstream = 10 + 2 = 12 km/h. Time = Distance/Speed = 50/12 = 4.17 hours.
Correct Answer: C — 4 hours
Q. A boat can go 15 km upstream and 21 km downstream in 3 hours. If the speed of the boat in still water is 10 km/h, what is the speed of the stream?
A.2 km/h
B.3 km/h
C.4 km/h
D.5 km/h
Solution
Let the speed of the stream be x km/h. The speed upstream = (10 - x) km/h and downstream = (10 + x) km/h. Time taken upstream = 15/(10 - x) and downstream = 21/(10 + x). Therefore, (15/(10 - x)) + (21/(10 + x)) = 3. Solving gives x = 3 km/h.
Correct Answer: B — 3 km/h
Q. A boat can go 15 km upstream in 3 hours. What is the speed of the boat in still water if the speed of the current is 3 km/h?
A.4 km/h
B.5 km/h
C.6 km/h
D.7 km/h
Solution
Speed upstream = Distance/Time = 15 km / 3 h = 5 km/h. Speed of boat in still water = Speed upstream + Speed of current = 5 km/h + 3 km/h = 8 km/h.
Correct Answer: B — 5 km/h
Q. A boat can go 15 km/h in still water. If the speed of the current is 3 km/h, what is the speed of the boat downstream?
A.12 km/h
B.15 km/h
C.18 km/h
D.21 km/h
Solution
Speed downstream = Speed of boat + Speed of current = 15 + 3 = 18 km/h.
Correct Answer: C — 18 km/h
Q. A boat can go 20 km upstream in 5 hours. If the speed of the boat in still water is 8 km/h, what is the speed of the stream?
A.1 km/h
B.2 km/h
C.3 km/h
D.4 km/h
Solution
Let the speed of the stream be x km/h. Upstream speed = (8 - x) km/h. Therefore, 20/(8 - x) = 5. Solving gives x = 2 km/h.
Correct Answer: B — 2 km/h
Q. A boat can go 24 km downstream in 3 hours. If the speed of the boat in still water is 10 km/h, what is the speed of the current?
A.2 km/h
B.4 km/h
C.6 km/h
D.8 km/h
Solution
Speed downstream = Distance/Time = 24 km / 3 h = 8 km/h. Speed of current = Speed downstream - Speed of boat in still water = 8 km/h - 10 km/h = -2 km/h (not possible).
Correct Answer: B — 4 km/h
Q. A boat can go 25 km upstream in 5 hours. If the speed of the boat in still water is 7 km/h, what is the speed of the stream?
A.1 km/h
B.2 km/h
C.3 km/h
D.4 km/h
Solution
Let the speed of the stream be x km/h. Upstream speed = (7 - x) km/h. Therefore, 25/(7 - x) = 5. Solving gives x = 2 km/h.
Correct Answer: B — 2 km/h
Q. A boat can go 36 km upstream in 6 hours. If the speed of the current is 2 km/h, what is the speed of the boat in still water?
A.6 km/h
B.8 km/h
C.10 km/h
D.12 km/h
Solution
Speed upstream = Distance/Time = 36 km / 6 h = 6 km/h. Speed of boat in still water = Speed upstream + Speed of current = 6 km/h + 2 km/h = 8 km/h.
Correct Answer: B — 8 km/h
Q. A boat can travel 40 km upstream in 8 hours. If the speed of the current is 4 km/h, what is the speed of the boat in still water?
A.6 km/h
B.8 km/h
C.10 km/h
D.12 km/h
Solution
Speed upstream = Distance/Time = 40 km / 8 h = 5 km/h. Speed of boat in still water = Speed upstream + Speed of current = 5 km/h + 4 km/h = 9 km/h.
Correct Answer: C — 10 km/h
Q. A boat can travel 40 km upstream in 8 hours. If the speed of the stream is 2 km/h, what is the speed of the boat in still water?
A.4 km/h
B.6 km/h
C.8 km/h
D.10 km/h
Solution
Let the speed of the boat in still water be y km/h. Upstream speed = (y - 2) km/h. Therefore, (y - 2) * 8 = 40. Solving gives y = 8 km/h.
Correct Answer: C — 8 km/h
Q. A boat can travel 80 km downstream in 8 hours. If the speed of the current is 4 km/h, what is the speed of the boat in still water?
A.8 km/h
B.10 km/h
C.12 km/h
D.14 km/h
Solution
Speed downstream = Distance/Time = 80 km / 8 h = 10 km/h. Speed of boat in still water = Speed downstream - Speed of current = 10 km/h - 4 km/h = 6 km/h.
Correct Answer: C — 12 km/h
Q. A boat can travel at 10 km/h in still water. If it takes 2 hours to go upstream and 1 hour to return downstream, what is the speed of the current?
A.2 km/h
B.3 km/h
C.4 km/h
D.5 km/h
Solution
Let the speed of the current be x. Upstream speed = 10 - x, Downstream speed = 10 + x. Time upstream = 2 hours, Time downstream = 1 hour. Thus, 2(10 - x) = Distance and 1(10 + x) = Distance. Equating gives x = 3 km/h.
Correct Answer: B — 3 km/h
Q. A boat can travel at 12 km/h in still water. If it takes 3 hours to go upstream and 2 hours to return downstream, what is the speed of the current?
A.1 km/h
B.2 km/h
C.3 km/h
D.4 km/h
Solution
Let the speed of the current be x. Upstream speed = 12 - x, Downstream speed = 12 + x. Distance = 3(12 - x) = 2(12 + x). Solving gives x = 2 km/h.
Correct Answer: B — 2 km/h
Q. A boat can travel at 18 km/h in still water. If it takes 4 hours to go upstream and 3 hours to return downstream, what is the speed of the current?
A.2 km/h
B.3 km/h
C.4 km/h
D.5 km/h
Solution
Let the speed of the current be x. Upstream speed = 18 - x, Downstream speed = 18 + x. Distance = 4(18 - x) = 3(18 + x). Solving gives x = 3 km/h.
Correct Answer: C — 4 km/h
Q. A boat takes 3 hours to go 36 km upstream and 2 hours to return downstream. What is the speed of the stream?
A.2 km/h
B.3 km/h
C.4 km/h
D.5 km/h
Solution
Let the speed of the stream be x km/h. Upstream speed = (y - x) and downstream speed = (y + x). From the equations, we can derive that x = 2 km/h.
Correct Answer: A — 2 km/h
Q. A boat travels 20 km downstream in 2 hours. If the speed of the current is 2 km/h, what is the speed of the boat in still water?
A.8 km/h
B.10 km/h
C.12 km/h
D.14 km/h
Solution
Speed downstream = Distance/Time = 20 km / 2 h = 10 km/h. Speed of boat in still water = Speed downstream - Speed of current = 10 km/h - 2 km/h = 8 km/h.
Correct Answer: B — 10 km/h
Q. A boat travels 30 km downstream in 2 hours. If the speed of the current is 5 km/h, what is the speed of the boat in still water?
A.10 km/h
B.15 km/h
C.20 km/h
D.25 km/h
Solution
Speed downstream = Distance/Time = 30/2 = 15 km/h. Speed of boat = Speed downstream - Speed of current = 15 - 5 = 10 km/h.
Correct Answer: C — 20 km/h
Q. A boat travels 30 km downstream in 2 hours. If the speed of the stream is 5 km/h, what is the speed of the boat in still water?
A.10 km/h
B.15 km/h
C.20 km/h
D.25 km/h
Solution
Let the speed of the boat in still water be y km/h. Downstream speed = y + 5 km/h. Therefore, (y + 5) * 2 = 30. Solving gives y = 10 km/h.
Correct Answer: B — 15 km/h
Q. A boat travels 40 km upstream in 5 hours. If the speed of the boat in still water is 8 km/h, what is the speed of the current?
A.1 km/h
B.2 km/h
C.3 km/h
D.4 km/h
Solution
Speed upstream = Distance/Time = 40/5 = 8 km/h. Thus, 8 - x = 8, so x = 0. The current speed is 0 km/h.
Correct Answer: D — 4 km/h
Q. A boat travels 50 km downstream in 5 hours and returns upstream in 10 hours. What is the speed of the stream?
A.2 km/h
B.3 km/h
C.4 km/h
D.5 km/h
Solution
Let the speed of the stream be x km/h. Downstream speed = (y + x) and upstream speed = (y - x). From the equations, we can derive that x = 4 km/h.
Correct Answer: C — 4 km/h
Q. A boat travels 50 km downstream in 5 hours. If the speed of the current is 5 km/h, what is the speed of the boat in still water?
A.8 km/h
B.10 km/h
C.12 km/h
D.14 km/h
Solution
Speed downstream = Distance/Time = 50 km / 5 h = 10 km/h. Speed of boat in still water = Speed downstream - Speed of current = 10 km/h - 5 km/h = 5 km/h.
Correct Answer: B — 10 km/h
Q. If a boat can go 25 km/h in still water and the current is 5 km/h, how long will it take to travel 60 km downstream?
A.1.5 hours
B.2 hours
C.2.5 hours
D.3 hours
Solution
Speed downstream = 25 + 5 = 30 km/h. Time = Distance/Speed = 60/30 = 2 hours.
Correct Answer: B — 2 hours
Q. If a boat can travel 30 km upstream in 5 hours, what is the speed of the current if the speed of the boat in still water is 8 km/h?
A.2 km/h
B.3 km/h
C.4 km/h
D.5 km/h
Solution
Speed upstream = Distance/Time = 30 km / 5 h = 6 km/h. Speed of current = Speed of boat in still water - Speed upstream = 8 km/h - 6 km/h = 2 km/h.
Correct Answer: A — 2 km/h
Q. If a boat can travel 60 km downstream in 3 hours, and the speed of the stream is 6 km/h, what is the speed of the boat in still water?
A.18 km/h
B.20 km/h
C.22 km/h
D.24 km/h
Solution
Let the speed of the boat in still water be y km/h. Downstream speed = y + 6 km/h. Therefore, (y + 6) * 3 = 60. Solving gives y = 18 km/h.
Correct Answer: B — 20 km/h
Q. If a boat can travel 60 km downstream in 4 hours, what is the speed of the current if the speed of the boat in still water is 15 km/h?
A.3 km/h
B.4 km/h
C.5 km/h
D.6 km/h
Solution
Speed downstream = Distance/Time = 60 km / 4 h = 15 km/h. Speed of current = Speed downstream - Speed of boat in still water = 15 km/h - 15 km/h = 0 km/h.
Correct Answer: C — 5 km/h
Q. If a boat goes 20 km upstream in 4 hours, what is the speed of the current if the speed of the boat in still water is 10 km/h?
A.2 km/h
B.3 km/h
C.4 km/h
D.5 km/h
Solution
Speed upstream = Speed of boat - Speed of current. Distance = 20 km, Time = 4 hours. Speed upstream = 20/4 = 5 km/h. Thus, 10 - x = 5, so x = 5 km/h.
