## Aptitude Boats and Streams Concepts, Important Formulas, Solved Questions & Answers,

## Boats and Streams

**Still water:**The water of a river or any other water body which is not flowing is known as still water.**Stream:**It is the flowing water of a river that is moving at a certain speed.**Upstream:**The boat or a swimmer moving against the stream is known as moving upstream i.e., against the flow of water.**Downstream:**The boat or a swimmer moving along the stream is known as moving downstream i.e., along the flow of water.

### Important Formulas

- Speed of this boat downstream = (u + v) km/hr
- Speed of this boat upstream = (u -v) km/hr.
- Also, if the downstream speed is ‘a’ km/hr (suppose) and the rate upstream is b km/hr, then:
- Speed in still water will be = [1/2](a + b) km/hr
- Rate of stream is = [1/2](a – b) km/hr
- When the distance covered downstream and upstream are equal, we can write: (u + v)t1 = (u – s)t2 where t1 and t2 are a different time taken.

### Aptitude Boats and Streams Questions with Answers

**1. In still water, a boat can fly at a speed of 13 km/hr. If the stream speed is 4 km / h, find the time the ship has taken to go 68 km downstream.**

- A. 2 hours
- B. 3 hours
- C. 4 hours
- D. 5 hours

**Answer:** Option C (4 hours)

**2. A boat that runs upstream takes 8 hours 48 minutes to cover a certain distance, whereas it takes 4 hours to cover the same downstream range. What is the ratio between boat speed and speed of water current, respectively?**

- A. 2: 1
- B. 3: 2
- C. 8 : 3
- D. Cannot be determined

**Answer:** Option C (8 : 3)

**3. A man rowing 12 km upstream takes 20 minutes, which is a third longer than the time he takes downstream on his journey. What is its speed in still water?**

- A. 41 km/hr
- B. 36 km/hr
- C. 42 km/hr
- D. 45 km/hr

**Answer:** Option C (42 km/hr)

**4. How long will it take to row 20 km upstream if the stream is allowed to row 10 km in 10 minutes in still water, and the same distance in 8 minutes?**

- A. 12 min
- B. 13.33 min
- C. 24 min
- D. 26.67 min

**Answer:** Option D (26.67 min)

**5. A boat’s speed in still water is 15 km / h, and a current average of 3 km / h. In 12 minutes the distance traveled downstream is:**

- A. 1.2 km
- B. 1.8 km
- C. 2.4 km
- D. 3.6 km

**Answer:** Option D (3.6 km)

**6. A boat traveling 36 miles downstream takes 90 minutes less than traveling the same distance upstream. If the boat’s speed in still water is 10 mph, the flux speed is:**

- A. 2 mph
- B. 2.5 mph
- C. 3 mph
- D. 4 mph

**Answer:** Option A (2 mph)

**7. In Hours a man rows ‘k’ km upstream and downstream again to the same point. In still water, the rowing speed is s km/hr, and the stream rate is r km/hr. Then there is**

- A. (s
^{2}-r^{2}) =2sk /H - B. (r + s) = kH / (r -s)
- C. rs = kH
- D. None of the above

**Answer:** Option A ((s2-r2) =2sk /H)

**8. A man rows upstream 24 km in 6 hours, and downstream a distance of 35 km in 7 hours. The man pace in still water is then**

- A. 4.5 km/hr
- B. 4 km/hr
- C. 5 km/hr
- D. 5.5 km/hr

**Answer:** Option A (4.5 km/hr)

**9. In 6 hours, a man may row 30 km upstream. If the man velocity in still water is 6 km / h, find out how much downstream he can row in 10 hours.**

- A. 70 km
- B. 140 km
- C. 200 km
- D. 250 km

**Answer:** Option A (70 km)

**10. For 1 hour, a boatman travels 2 km toward the streams current and goes 1 km along with the current for 10 minutes. How long does it take in stationary water for 5 km to go?**

- A. 40 minutes
- B. 1 hour
- C. 1 hr 15 min
- D. 1 hr 30 min

**Answer:** Option C (1 hr 15 min)