# Boat and Stream Aptitude Questions with Solutions:

#### Overview:

 Questions and Answers Type: MCQ (Multiple Choice Questions). Main Topic: Quantitative Aptitude. Quantitative Aptitude Sub-topic: Time Speed and Distance Aptitude Questions and Answers. Number of Questions: 10 Questions with Solutions.

1. If a man swims $$10 \ km$$ upstream and $$12 \ km$$ downstream, taking $$2 \ hours$$ each time, then find the speed of stream?

1. $$0.3 \ km/hr$$
2. $$0.4 \ km/hr$$
3. $$0.5 \ km/hr$$
4. $$1.0 \ km/hr$$

Answer: (c) $$0.5 \ km/hr$$

Solution: Given, speed of upstream $$(U_s) = \frac{10}{2} = 5 \ km/hr$$

speed of downstream $$(D_s) = \frac{12}{2} = 6 \ km/hr$$

then speed of stream, $$S_s = \frac{D_s - U_s}{2}$$ $$= \frac{6 - 5}{2} = 0.5 \ km/hr$$

1. If a girl can swim $$18 \ km$$ upstream and $$26 \ km$$ downstream, taking $$2 \ hours$$ each time, then find speed of the girl in still water?

1. $$10 \ km/hr$$
2. $$11 \ km/hr$$
3. $$12 \ km/hr$$
4. $$15 \ km/hr$$

Answer: (b) $$11 \ km/hr$$

Solution: Given, speed of upstream $$(U_s) = \frac{18}{2} = 9 \ km/hr$$

speed of downstream $$(D_s) = \frac{26}{2} = 13 \ km/hr$$

then speed of the girl in still water, $$B_s = \frac{D_s + U_s}{2}$$ $$= \frac{9 + 13}{2} = 11 \ km/hr$$

1. If a boat goes $$30 \ km$$ upstream and $$45 \ km$$ downstream, taking $$3 \ hours$$ each time, then find the speed of stream and speed of the boat in still water?

1. $$S_s = 2.5 \ km/hr$$, $$B_s = 12.5 \ km/hr$$
2. $$S_s = 3.5 \ km/hr$$, $$B_s = 13.5 \ km/hr$$
3. $$S_s = 2.5 \ km/hr$$, $$B_s = 15.5 \ km/hr$$
4. $$S_s = 5.5 \ km/hr$$, $$B_s = 12.5 \ km/hr$$

Answer: (a) $$S_s = 2.5 \ km/hr$$, $$B_s = 12.5 \ km/hr$$

Solution: Given, speed of upstream $$(U_s) = \frac{30}{3} = 10 \ km/hr$$

speed of downstream $$(D_s) = \frac{45}{3} = 15 \ km/hr$$then speed of stream, $$S_s = \frac{D_s - U_s}{2}$$ $$= \frac{15 - 10}{2} = 2.5 \ km/hr$$ then speed of the boat in still water, $$B_s = \frac{D_s + U_s}{2}$$ $$= \frac{15 + 10}{2} = 12.5 \ km/hr$$

1. A man swims from point A to B and takes $$2 \ hours$$ for traveling upstream from point A to B and coming back from point B to A downstream. If the speed of stream is $$10 \ km/hr$$ and speed of the man in still water is $$12 \ km/hr$$, then find the distance between point A and B?

1. $$2.58 \ km$$
2. $$2.67 \ km$$
3. $$3.67 \ km$$
4. $$3.58 \ km$$

Answer: (c) $$3.67 \ km$$

Solution: Given, speed of stream $$(S_s) = 10 \ km/hr$$

speed of the man in still water $$(B_s) = 12 \ km/hr$$, then

speed of upstream $$(U_s) = B_s - S_s$$ $$= 12 - 10 = 2 \ km/hr$$

speed of downstream $$(D_s) = B_s + S_s$$ $$= 12 + 10 = 22 \ km/hr$$

Let the distance between point A and B = $$x \ km$$, then $$\frac{x}{22} + \frac{x}{2} = 2$$ $$\frac{12 \ x}{22} = 2$$ $$12 \ x = 44$$ $$x = \frac{44}{12} = 3.67 \ km$$ Hence the distance between the point A and B = $$3.67 \ km$$

1. If a boat goes downstream with the speed of $$16 \ km/hr$$ and upstream with the speed of $$14 \ km/hr$$, then find the speed of the boat in still water?

1. $$12 \ km/hr$$
2. $$13 \ km/hr$$
3. $$14 \ km/hr$$
4. $$15 \ km/hr$$

Answer: (d) $$15 \ km/hr$$

Solution: Given, speed of downstream $$(D_s) = 16 \ km/hr$$

speed of upstream $$(U_s) = 14 \ km/hr$$

then speed of the boat in still water, $$B_s = \frac{U_s + D_s}{2}$$ $$= \frac{14 + 16}{2}$$ $$= \frac{30}{2} = 15 \ km/hr$$

1. If a boat goes downstream at the speed of $$9 \ km/hr$$ and speed of stream is $$4 \ km/hr$$, then find the speed of boat in still water?

1. $$5 \ km/hr$$
2. $$6 \ km/hr$$
3. $$4 \ km/hr$$
4. $$2 \ km/hr$$

Answer: (a) $$5 \ km/hr$$

Solution: Given, speed of downstream $$(D_s) = 9 \ km/hr$$

speed of stream $$(S_s) = 4 \ km/hr$$

then speed of the boat in still water, $$B_s = D_s - S_s$$ $$= 9 - 4 = 5 \ km/hr$$

1. A girl can swim $$28 \ km$$ downstream, taking $$4 \ hours$$. If speed of stream is $$3 \ km/hr$$, then find the speed of upstream?

1. $$1 \ km/hr$$
2. $$2 \ km/hr$$
3. $$3 \ km/hr$$
4. $$5 \ km/hr$$

Answer: (a) $$1 \ km/hr$$

Solution: Given, speed of downstream $$(D_s) = \frac{28}{4} = 7 \ km/hr$$

speed of stream $$(S_s) = 3 \ km/hr$$, then $$S_s = \frac{D_s - U_s}{2}$$ $$3 = \frac{7 - U_s}{2}$$ $$6 = 7 - U_s$$ $$U_s = 1 \ km/hr$$

1. A boat goes $$16 \ km$$ upstream, taking $$2 \ hours$$. If speed of stream is $$2 \ km/hr$$, then find the speed of downstream?

1. $$15 \ km/hr$$
2. $$13 \ km/hr$$
3. $$12 \ km/hr$$
4. $$10 \ km/hr$$

Answer: (c) $$12 \ km/hr$$

Solution: Given, speed of upstream $$(U_s) = \frac{16}{2} = 8 \ km/hr$$

speed of stream $$(S_s) = 2 \ km/hr$$, then $$S_s = \frac{D_s - U_s}{2}$$ $$2 = \frac{D_s - 8}{2}$$ $$4 = D_s - 8$$ $$D_s = 12 \ km/hr$$

1. A boat goes downstream with the speed of $$25 \ km/hr$$. If the speed of the boat in still water is $$15 \ km/hr$$, then find the speed of upstream?

1. $$2 \ km/hr$$
2. $$3 \ km/hr$$
3. $$4 \ km/hr$$
4. $$5 \ km/hr$$

Answer: (d) $$5 \ km/hr$$

Solution: Given, speed of downstream $$(D_s) = 25 \ km/hr$$

speed of boat in still water $$(B_s) = 15 \ km/hr$$, then $$B_s = \frac{D_s + U_s}{2}$$ $$15 = \frac{25 + U_s}{2}$$ $$30 = 25 + U_s$$ $$U_s = 5 \ km/hr$$

1. A boat goes upstream with the speed of $$22 \ km/hr$$. If the speed of the boat in still water is $$8 \ km/hr$$, then find the speed of downstream?

1. $$12 \ km/hr$$
2. $$13 \ km/hr$$
3. $$14 \ km/hr$$
4. $$15 \ km/hr$$

Answer: (c) $$14 \ km/hr$$

Solution: Given, speed of upstream $$(U_s) = 22 \ km/hr$$

speed of the boat in still water $$(B_s) = 18 \ km/hr$$, then $$B_s = \frac{D_s + U_s}{2}$$ $$18 = \frac{D_s + 22}{2}$$ $$36 = D_s + 22$$ $$D_s = 14 \ km/hr$$