Aptitude - Boats and Streams - Discussion
Discussion Forum : Boats and Streams - General Questions (Q.No. 8)
8.
A boat takes 90 minutes less to travel 36 miles downstream than to travel the same distance upstream. If the speed of the boat in still water is 10 mph, the speed of the stream is:
Answer: Option
Explanation:
Let the speed of the stream x mph. Then,
Speed downstream = (10 + x) mph,
Speed upstream = (10 - x) mph.
 |
36 | - | 36 | = | 90 |
| (10 - x) | (10 + x) | 60 |
72x x 60 = 90 (100 - x2)
x2 + 48x - 100 = 0
(x+ 50)(x - 2) = 0
x = 2 mph.
Discussion:
85 comments Page 5 of 9.
Anomii said:
7 years ago
I solved like this;
36/t =10+x.
36/t+1.3=10-x.I am not getting the answer. Please anyone help me.
36/t =10+x.
36/t+1.3=10-x.I am not getting the answer. Please anyone help me.
Kavitha said:
1 decade ago
(x+ 50)(x - 2) = 0 how this step come from x2 + 48x + 100 = 0.
This equations please explain?
This equations please explain?
Sandeep said:
1 decade ago
In 4th problem '+' is used why '-' hear.
36/(10 - x) "-" 36/(10 + x) = 90/60.
36/(10 - x) "-" 36/(10 + x) = 90/60.
Manjunath said:
8 years ago
Why had we done subtraction here? it means why won't we did addition? Please explain.
Ram said:
1 decade ago
Hello am not following how to take '+' n '-'in b/w: 36/(10-x) '-' 36/(10+x) = 90/60.
Honey said:
1 decade ago
x2+48x-100 = 0.
x2+50x+2x-100 = 0.
x(x+50)-2(x+50) = 0.
(x+50)(x-2) = 0.
x = 2.
x2+50x+2x-100 = 0.
x(x+50)-2(x+50) = 0.
(x+50)(x-2) = 0.
x = 2.
Annil Gani said:
5 years ago
Upstream ditsnace = downstream distance.
90/60*(10-x) = (10+s),
300 = 150*x,
X = 2.
90/60*(10-x) = (10+s),
300 = 150*x,
X = 2.
(10)
Ram said:
1 decade ago
72x x 60 = 90 (100 - x2)
x2 + 48x + 100 = 0
How this step comes? pls tell me.
x2 + 48x + 100 = 0
How this step comes? pls tell me.
Hussain peera said:
1 decade ago
Can we find solution to this problem in different manner it means any shortcut.
Saranya said:
9 years ago
(90/60)min = (36/(10 - x)) - (36/(10 + x));
How the minus comes between this?
How the minus comes between this?
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