Dear Reader, Below are three easy boat problems to practice for Wipro and other company papers carrying similar questions.

Question 1

The students of Vidya Mandir Secondary school, Jalpaiguri went for an excursion. It was seen that a boat travels at 14.5 km per hour when it goes along with the stream. By the time he starts returning the speed of the river doubled than its original value due to a sudden storm. The speed of the boat is 7 km per hour when it goes against the river stream. What is the speed of boat per hour?

a) 10 km b) 8 km c) 12 km d) 7 km

Answer : c) 12 km

Solution :

Let the speed of the boat be B and the speed of stream be S.
Equation for travel along with Stream : B + S = 14.5 ----> eq 1
During the travel against the stream, the speed of the stream temporarily doubled.
Therefore, Equation for travel against the stream = B - 2S = 7 ----> eq 2 (NOTE: We are using 2S instead of S in the equation as speed of the stream has temporarily doubled when he travelled against the stream)
eq 1 - eq 2 => 3S = 7.5
or S = 2.5 kph
Substitute S = 2.5 in eq 1
B = 14.5 - 2.5 = 12

Question 2

A boat man was driving a boat during a cyclonic storm during which time the speed of the river was considerably high than normal times. He found that the boat travelled 222 km in three hours when he was driving along with the river. But when he drove the boat against the river the boat travelled 100 km in two hours. What is the speed of the river per hour during cyclonic storm?

a) 10 km b) 12 km c) 8 km d) 9 km

Answer : b) 12 km

Solution :

Let the speed of the boat be B and the speed of the river be S.
B + S = 222/3 ----> eq 1
B - S = 100/2 ----> eq 2
Adding equations 1 and 2 we get : 2B = 300 + 444 / 6
2B = 744/6
2B = 124
B = 62
Substituting B = 62 in eq 2 we get,
S = B - 100/2 = 62 - 50 = 12

Question 3

Maruti Cruisers sailed 132 km along with the river in six hours. Suddenly the boat had to return to the starting point and it started returning against the river and this time the Cruiser travelled at 128 km in eight hours. By how much percentage Cruiser's speed exceeds the speed of the River ?

a) 533.33% b) 444.44% c) 267.67% d) none of these.

Answer : a) 533.33%

Solution :

Speed of boat along with the river per hour = 22 km (132 divided by 6)
Speed of boat against the river per hour = 16 km (128 divided by 8)
B + S = 22 ----> eq 1
B – S = 16 ----> eq 2
Adding equations 1 and 2, we get : B+S-B+S = 22 -16 = 6 =2S
S = 3 km/hour
Substituting S= 3, in eq 1 we get : B + 3 = 22
B = 22 - 3 = 19 km /hour
Cruiser's speed exceeds the speed of the River By : Cruiser's Speed - River Speed / River Speed x 100 = B - S / S X 100% = 19 - 3/ 3 X 100 = 16/3 X 100 = 533.33%