Aptitude - Boats and Streams - Discussion
Discussion Forum : Boats and Streams - General Questions (Q.No. 4)
4.
A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:
Answer: Option
Explanation:
Let the speed of the stream be x km/hr. Then,
Speed downstream = (15 + x) km/hr,
Speed upstream = (15 - x) km/hr.
 |
30 | + | 30 | = 4 | 1 |
| (15 + x) | (15 - x) | 2 |
 |
900 | = | 9 |
| 225 - x2 | 2 |
9x2 = 225
x2 = 25
x = 5 km/hr.
Video Explanation: https://youtu.be/lMFnNB3YQOo
Discussion:
63 comments Page 4 of 7.
Smruthi said:
1 decade ago
What is the difference between 4 sum and 8 sum having the same description?
John said:
1 decade ago
How it is possible to multiply the speed of upstream and downstream?
Gourav Shervegar said:
8 years ago
Why the speed of upstream is 15-x and speed of downstream is 15+x?
Anjali said:
9 years ago
Please explain it in an easy way, which will be helpful for me.
Aary said:
1 decade ago
How did we get 30*30 = 900?
Are we taking 30 common or what?
Are we taking 30 common or what?
Breetha said:
8 years ago
A little confusion in simplification. How 900 came? Explain.
Eve said:
9 years ago
Why is it downstream + something and upstream - something?
Neha said:
1 decade ago
By solving the fraction 4*2=8, n 8+1=9, so the ans is 9/2
Ranjith said:
9 years ago
4 hours and 30 minutes as 9/2. Total in terms of km/ hr.
Ezhil said:
1 decade ago
Hai, Mr. Rajesh Kumar, can you explain me in brief?
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