MCQ Test: Boat and Stream- 1 - Bank Exams MCQ

Speed downstrem = (12 + 4)km/hr = 16 km/hr;
Speed upstream = (12 - 4) km/hr = 8 km/hr.
Let the distance between A and B be x km, Then,

⇔ 2x/16 = 19 ⇔ x = 152 km.

Let the speed of the motorboat in still water be x kmph. Then,
Speed downstream = (x + 2) kmph; Speed upstream = (x – 2) kmph.

⇒  11x² – 242x + 2x – 44 = 0  ⇔  (x – 22)(11x + 2) = 0  ⇔  x = 22.
Hence, speed of motorboat in still water = 22 kmph.
Hence, option D is correct.

To solve this question, we can apply a short trick approach;

Given,
x = Person speed = 18 kmph
n = the no. of times of hours taken by the boat in the 2nd scenario (upstream) = 3
By the short trick approach, we get

Hence, option C is correct.

Rate upstream = 8 – 1.5 = 6.5 kmph
Rate downstream = 8 + 1.5 = 9.5 kmph
Time taken to go upstream = 61.75/6.5 = 9.5 hr.
Time taken to go downstream = 61.75/9.5 = 6.5 hr.
Total time = 9.5 + 6.5 = 16 hrs.
Hence, option C is correct.

Given,

Upstream rate = 3.5 kmph, Speed of a man in still water  = 5 kmph

Let the downstream rate be x kmph, then

By the short trick approach, we get

Speed of the man (boat) in still water = 1/2

[DOWNSTREAM rate + UPSTREAM rate]

⇒ 5 = 1/2 (x + 3.5)  or   x = 6.5 kmph

Hence, option C is correct.

Speed downstream
= (13 + 4) km/hr
= 17 km/hr
Time taken to travel 68 km downstream
= 68/17 hours
= 4 hours

Let the man's rate upstream be x kmph and that downstream be y kmph.
Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.

∴ Required ratio

Speed in still water
= 1/2 (11 + 5) kmph
= 8 kmph

Speed downstream
= (15 + 3) kmph
= 18 kmph
Distance travelled

= 3.6 km

Speed downstream = (5 + 1) kmph = 6 kmph
Speed upstream = (5 - 1) kmph = 4 kmph
Let the required distance be x km
Then,

⇒ 2x + 3x = 12
⇒ 5x = 12
⇒ x = 2.4 km

Rate upstream = (7/42 × 60) kmph = 10 kmph.
Speed of stream = 3 kmph
Let speed in still water be x km/hr. Then, speed upstream = (x – 3) km/hr.
∴   x – 3 = 10   OR   x = 13 km/hr.

Rate in still water = 1/2 (10 + 7) km/hr = 8.5 km/hr
Rate of current = 1/2 (10 – 7) km/hr = 1.5 km/hr.

Let the upstream = x kmph and rate downstream = y kmph.
Then,

Adding (i) and (ii) we get:

Subtracting (i) and (ii), we get:

Adding (iii) and (iv), we get 2/x = 6/24 or  x = 8.
So,

∴  Speed upstream = 8 kmph, Speed downstream = 12 kmph.
Hence, rate of current 1/2(12 – 8) kmph = 2 kmph.
Hence, option C is correct.

Speed downstream
= (15/2 + 1.5) kmph
= (7.5 + 1.5) kmph
= 9 kmph;
Speed upstream
= (15/2  – 1.5) kmph
= (7.5 – 1.5) kmph
= 6 kmph.
Let the required distance be x km. Then,


⇔  5x = 15  ⇔  x = 3
Hence, the required distance is 3 km.

Let rate upstream = x km/hr and rate downstream = y km/hr.
Then, 40/x + 55/y = 13 ... (i)    and
30/x + 44/y = 10    .... (ii)
Multiplying (ii) by 4 and (i) by 3 and subtracting,
we get: 11/y = 1 or y = 11.
Substituting y = 11 in (i), we get: x = 5.
∴ Rate in still water = 1/2 (11 + 5) kmph = 8 kmph.
Rate in current = 1/2(11 – 5) kmph = 3 kmph.
Hence, option B is correct.  

Rate downstream

Rate upstream = 2km/hr
Speed in still water
= 1/2 (6 + 2)km/hr = 4km/hr
∴Required time
= 5/4 hrs
= 1¹/₄ hrs
= 1hr 15min.

Speed upstream = 7.5 kmph
Speed downstream = 10.5 kmph
∴ Total time taken

= 24 hours

Suppose he move 4 km downstream in x hours
Then,
Speed downstream = 4/x km/hr
Speed upstream = 3/x km/hr

So, Speed downstream = 8 km/hr
Speed upstream = 6 km/hr
∴ Rate of the stream
= 1/2 (8 - 6) km/hr
= 1 km/hr

Speed of man in still water, x = 6 km/h
Speed of current, y = 2 km/h
Let distance = M
According to question
Upstream time = Downstream time + 4

M = 32
∴ Distance = 32 km

Speed of downstream
D = 12 km/h
Speed of upstream
U = 8 km/h
Speed of boat in still water
= D + U/2
= 20/2
= 10 km/h
Time taken by the boat in still water

= 2.4 hours