Boats and streams
Ten quantitative aptitude questions, each marked as you answer.
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A boat covers 44 km downstream in 4 hours and 21 km upstream in 3 hours. What is the speed of the boat in still water?
Answer and working
Answer A
Downstream speed = 44 ÷ 4 = 11 km/h; upstream = 21 ÷ 3 = 7 km/h. Boat = (11 + 7) ÷ 2 = 9 km/h.
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A boat covers 44 km downstream in 2 hours and 70 km upstream in 5 hours. What is the speed of the boat in still water?
Answer and working
Answer D
Downstream speed = 44 ÷ 2 = 22 km/h; upstream = 70 ÷ 5 = 14 km/h. Boat = (22 + 14) ÷ 2 = 18 km/h.
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A boat covers 125 km downstream in 5 hours and 60 km upstream in 4 hours. What is the speed of the boat in still water?
Answer and working
Answer A
Downstream speed = 125 ÷ 5 = 25 km/h; upstream = 60 ÷ 4 = 15 km/h. Boat = (25 + 15) ÷ 2 = 20 km/h.
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A boat covers 88 km downstream in 4 hours and 42 km upstream in 3 hours. What is the speed of the stream?
Answer and working
Answer B
Downstream speed = 88 ÷ 4 = 22 km/h; upstream = 42 ÷ 3 = 14 km/h. Stream = (22 − 14) ÷ 2 = 4 km/h.
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A boat covers 66 km downstream in 3 hours and 108 km upstream in 6 hours. What is the speed of the stream?
Answer and working
Answer A
Downstream speed = 66 ÷ 3 = 22 km/h; upstream = 108 ÷ 6 = 18 km/h. Stream = (22 − 18) ÷ 2 = 2 km/h.
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A boat covers 110 km downstream in 5 hours and 36 km upstream in 2 hours. What is the speed of the boat in still water?
Answer and working
Answer B
Downstream speed = 110 ÷ 5 = 22 km/h; upstream = 36 ÷ 2 = 18 km/h. Boat = (22 + 18) ÷ 2 = 20 km/h.
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A boat covers 96 km downstream in 4 hours and 36 km upstream in 3 hours. What is the speed of the stream?
Answer and working
Answer A
Downstream speed = 96 ÷ 4 = 24 km/h; upstream = 36 ÷ 3 = 12 km/h. Stream = (24 − 12) ÷ 2 = 6 km/h.
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A boat covers 44 km downstream in 2 hours and 42 km upstream in 3 hours. What is the speed of the stream?
Answer and working
Answer A
Downstream speed = 44 ÷ 2 = 22 km/h; upstream = 42 ÷ 3 = 14 km/h. Stream = (22 − 14) ÷ 2 = 4 km/h.
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A boat covers 60 km downstream in 3 hours and 60 km upstream in 5 hours. What is the speed of the stream?
Answer and working
Answer C
Downstream speed = 60 ÷ 3 = 20 km/h; upstream = 60 ÷ 5 = 12 km/h. Stream = (20 − 12) ÷ 2 = 4 km/h.
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A boat covers 105 km downstream in 5 hours and 60 km upstream in 4 hours. What is the speed of the stream?
Answer and working
Answer A
Downstream speed = 105 ÷ 5 = 21 km/h; upstream = 60 ÷ 4 = 15 km/h. Stream = (21 − 15) ÷ 2 = 3 km/h.
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