Dear Reader, below are three distance time questions that will surely make you think. First two are bit tricky while third is a conventional one. Hope you find these questions useful and interesting.
Question 1
Murali Manohar wanted to learn swimming. He took the assistance of famous swimming teacher Balajee for this purpose. Murali Manohar wanted to learn swimming along the river and against the river stream also. So he opted to swim against Cauvery river one day with a hat on his head. His hat fell into the river after he swimmed 2 km upward and thereafter he swam for 6 minutes. He wanted to take back the hat and he started swimming back and he caught the hat after further six minutes surprisingly at the place from where he started swimming in the river. What is the speed of the river?
a) 8 km/hr. B) 6 km/hr c) 12 km/hr d) 10 km/hr
Answer : d) 10 km/hr
Solution :
Murali Manohar was swimming against the river . His hat fell into the river after he crossed 2 km.
Murali Manohar swims for further six minutes and thereafter only he returns back to get the hat and swims along with the river.
Now Murali Manohar could get it after swimming further six minutes – the important point is that he gets it from the place where he started.
So, in the 12 minutes (6 + 6) the hat has run along with the river to the place from where he started – that means 2 km in 12 minutes. So speed of river is
60/12 x 2 = 10 km/hr
(For such problems calculated concentrated thinking will get the simple idea which will help us solve the problem.Instead if you think with lack of confidence – because you have not come across a similar problem earlier, your thinking process will be affected and you may not be able to get the answer. )
Question 2
Amitabh Bachchan and Abhishek Bachchan took a boat and drove against the stream. Both of them wore hats of different colours. After the boat has covered 3 km the hat of Abhishek Bachchan fell down. They could not realise it till they covered further 7 1/2 minutes. At this stage Amitabh asked Abhishek to turn the boat back and go along with the river and they could get the hat 2 km in front of the place where they started after further 7 1/2 minutes. What is the speed of the river?
a) 16 km b) 20 km c) 24 km
d) 28 km
Answer : a) 16 km.
Solution :
The hat has fallen 3 km from the starting point. It was traced back by them 2 km in front of the starting point. That means the hat after falling into the river has travelled 3 + (3 - 2) = 3 + 1 = 4 km in the total 7 1/2 + 7 1/2= 15 minutes along with the river in its speed.
So the speed of the river is 60/15 x 4 = 16 km/hour
Question 3
Ramaswamy rows in a boat at 9 km per hour in still water. If the river is running at 3 km/hour and Ramaswamy takes 45 minutes for rowing to a Ghat and back. How far is the Ghat from the place?
a) 4 km b)5 km c)2.5 km d) 3 km
Answer : d) 3 km
Solution :
Let the distance upto the Ghat be x km
Along with the river speed = 9 +3 = 12 km/hr
Against the river speed = 9 – 3 = 6 km/hr
Time for journey with stream + Time for journey against stream = Overall Time Taken
x / Speed along with river + x / Speed against the river = 3/4
x/12 + x/6 = 3/4
Simplifying x = 3 km