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. |

- A boat goes downstream at the speed of \(25 \ km/hr\). If the speed of stream is \(12 \ km/hr\), then find the speed of boat in still water?
- \(11 \ km/hr\)
- \(12 \ km/hr\)
- \(13 \ km/hr\)
- \(14 \ km/hr\)

Answer: (c) \(13 \ km/hr\)

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

speed of stream \((S_s) = 12 \ km/hr\)

then speed of boat in still water, $$ B_s = D_s - S_s $$ $$ B_s = 25 - 12 = 13 \ km/hr $$

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

speed of stream \((S_s) = 12 \ km/hr\)

then speed of boat in still water, $$ B_s = D_s - S_s $$ $$ B_s = 25 - 12 = 13 \ km/hr $$

- A swimmer goes downstream with the, speed of stream \(14 \ km/hr\). If speed of the swimmer in still water is \(28 \ km/hr\), then find the speed of downstream?
- \(40 \ km/hr\)
- \(42 \ km/hr\)
- \(44 \ km/hr\)
- \(45 \ km/hr\)

Answer: (b) \(42 \ km/hr\)

Solution: Given, speed of stream \((S_s) = 14 \ km/hr\)

speed of swimmer in still water \((B_s) = 28 \ km/hr\)

then speed of downstream, $$ B_s = D_s - S_s $$ $$ 28 = D_s - 14 = 42 \ km/hr $$

Solution: Given, speed of stream \((S_s) = 14 \ km/hr\)

speed of swimmer in still water \((B_s) = 28 \ km/hr\)

then speed of downstream, $$ B_s = D_s - S_s $$ $$ 28 = D_s - 14 = 42 \ km/hr $$

- A boat goes downstream with the speed of \(40 \ km/hr\). If the speed of boat in still water is \(30 \ km/hr\), then find the speed of stream?
- \(10 \ km/hr\)
- \(12 \ km/hr\)
- \(13 \ km/hr\)
- \(14 \ km/hr\)

Answer: (a) \(10 \ km/hr\)

Solution: Given, speed of downstream \((D_s) = 40 \ km/hr\)

speed of boat in still water \((B_s) = 30 \ km/hr\) then, $$ B_s = D_s - S_s $$ $$ 30 = 40 - S_s $$ $$ S_s = 10 \ km/hr $$

Solution: Given, speed of downstream \((D_s) = 40 \ km/hr\)

speed of boat in still water \((B_s) = 30 \ km/hr\) then, $$ B_s = D_s - S_s $$ $$ 30 = 40 - S_s $$ $$ S_s = 10 \ km/hr $$

- A girl swims \(30 \ km\) downstream in \(1 \ hour\). If the speed of stream is \(5 \ km/hr\), then find the speed of the girl in still water?
- \(20 \ km/hr\)
- \(22 \ km/hr\)
- \(25 \ km/hr\)
- \(27 \ km/hr\)

Answer: (c) \(25 \ km/hr\)

Solution: Given, speed of downstream \((D_s) = \frac{30}{1} = 30 \ km/hr\)

speed of stream \((S_s) = 5 \ km/hr\)

then speed of girl in still water, $$ B_s = D_s - S_s $$ $$ B_s = 30 - 5 = 25 \ km/hr $$

Solution: Given, speed of downstream \((D_s) = \frac{30}{1} = 30 \ km/hr\)

speed of stream \((S_s) = 5 \ km/hr\)

then speed of girl in still water, $$ B_s = D_s - S_s $$ $$ B_s = 30 - 5 = 25 \ km/hr $$

- A boat goes upstream with the speed of \(18 \ km/hr\). If speed of stream is \(5 \ km/hr\), then find the speed of boat in still water?
- \(23 \ km/hr\)
- \(22 \ km/hr\)
- \(21 \ km/hr\)
- \(20 \ km/hr\)

Answer: (a) \(23 \ km/hr\)

Solution: Given, speed of upstream \((U_s) = 18 \ km/hr\)

speed of stream \((S_s) = 5 \ km/hr\)

then speed of boat in still water, $$ B_s = U_s + S_s $$ $$ B_s = 18 + 5 = 23 \ km/hr $$

Solution: Given, speed of upstream \((U_s) = 18 \ km/hr\)

speed of stream \((S_s) = 5 \ km/hr\)

then speed of boat in still water, $$ B_s = U_s + S_s $$ $$ B_s = 18 + 5 = 23 \ km/hr $$

- A boat goes \(70 \ km\) upstream, taking \(2 \ hours\). If the speed of stream is \(20 \ km/hr\), then find the speed of boat in still water?
- \(52 \ km/hr\)
- \(53 \ km/hr\)
- \(54 \ km/hr\)
- \(55 \ km/hr\)

Answer: (d) \(55 \ km/hr\)

Solution: Given, speed of upstream \((U_s) = \frac{70}{2} = 35 \ km/hr\)

speed of stream \((S_s) = 20 \ km/hr\)

then speed of boat in still water, $$ B_s = U_s + S_s $$ $$ B_s = 35 + 20 = 55 \ km/hr $$

Solution: Given, speed of upstream \((U_s) = \frac{70}{2} = 35 \ km/hr\)

speed of stream \((S_s) = 20 \ km/hr\)

then speed of boat in still water, $$ B_s = U_s + S_s $$ $$ B_s = 35 + 20 = 55 \ km/hr $$

- If a boat goes \(12 \ km\) downstream in \(36 \ minutes\) and the speed of boat in still water is \(8 \ km/hr\), then find the speed of stream?
- \(10 \ km/hr\)
- \(12 \ km/hr\)
- \(13 \ km/hr\)
- \(15 \ km/hr\)

Answer: (b) \(12 \ km/hr\)

Solution: Given, speed of downstream \((D_s) = \frac{12}{36} \times 60 = 20 \ km/hr\)

speed of boat in still water \((B_s) = 8 \ km/hr\)

then speed of stream, $$ B_s = D_s - S_s $$ $$ 8 = 20 - S_s $$ $$ S_s = 12 \ km/hr $$

Solution: Given, speed of downstream \((D_s) = \frac{12}{36} \times 60 = 20 \ km/hr\)

speed of boat in still water \((B_s) = 8 \ km/hr\)

then speed of stream, $$ B_s = D_s - S_s $$ $$ 8 = 20 - S_s $$ $$ S_s = 12 \ km/hr $$

- If a man can swim upstream at the speed of \(7 \ km/hr\) and speed of stream is \(3 \ km/hr\), then find the speed of man in still water?
- \(15 \ km/hr\)
- \(13 \ km/hr\)
- \(12 \ km/hr\)
- \(10 \ km/hr\)

Answer: (d) \(10 \ km/hr\)

Solution: Given, speed of upstream \((U_s) = 7 \ km/hr\)

speed of stream \((S_s) = 3 \ km/hr\)

then speed of the man in still water, $$ B_s = U_s + S_s $$ $$ B_s = 7 + 3 = 10 \ km/hr $$

Solution: Given, speed of upstream \((U_s) = 7 \ km/hr\)

speed of stream \((S_s) = 3 \ km/hr\)

then speed of the man in still water, $$ B_s = U_s + S_s $$ $$ B_s = 7 + 3 = 10 \ km/hr $$

- A women can swim \(18 \ km\) downstream in \(10 \ minutes\). If the speed of stream is \(80 \ km/hr\), then find speed of the women in still water?
- \(28 \ km/hr\)
- \(25 \ km/hr\)
- \(24 \ km/hr\)
- \(22 \ km/hr\)

Answer: (a) \(28 \ km/hr\)

Solution: Given, speed of downstream \((D_s) = \frac{18}{10} \times 60 = 108 \ km/hr\)

speed of stream \((S_s) = 80 \ km/hr\)

then speed of the women in still water, $$ B_s = D_s - S_s $$ $$ B_s = 108 - 80 = 28 \ km/hr $$

Solution: Given, speed of downstream \((D_s) = \frac{18}{10} \times 60 = 108 \ km/hr\)

speed of stream \((S_s) = 80 \ km/hr\)

then speed of the women in still water, $$ B_s = D_s - S_s $$ $$ B_s = 108 - 80 = 28 \ km/hr $$

- A boat goes upstream with the speed of \(30 \ km/hr\). If the speed of boat in still water is \(45 \ km/hr\), then find the speed of stream?
- \(12 \ km/hr\)
- \(13 \ km/hr\)
- \(14 \ km/hr\)
- \(15 \ km/hr\)

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

Solution: Given, speed of upstream \((U_s) = 30 \ km/hr\)

speed of boat in still water \((B_s) = 45 \ km/hr\)

then speed of stream, $$ B_s = U_s + S_s $$ $$ 45 = 30 + S_s $$ $$ S_s = 15 \ km/hr $$

Solution: Given, speed of upstream \((U_s) = 30 \ km/hr\)

speed of boat in still water \((B_s) = 45 \ km/hr\)

then speed of stream, $$ B_s = U_s + S_s $$ $$ 45 = 30 + S_s $$ $$ S_s = 15 \ km/hr $$

Lec 1: Introduction to Time, Speed and Distance
Exercise-1
Lec 2: Concept of Train and Platform Case (1)
Exercise-2
Lec 3: Concept of Train and Platform Case (2)
Exercise-3
Lec 4: Concept of Train and Platform Case (3)
Exercise-4
Lec 5: Concept of Train and Platform Case (4)
Exercise-5
Lec 6: Concept of Acceleration
Exercise-6
Lec 7: Concept of Boat and Stream Case (1) and Case (2)
Exercise-7
Lec 8: Concept of Boat and Stream Case (3)
Exercise-8
Exercise-9
Exercise-10