Melody

I understand the problem of a teacher,  if I was you I would be equally frustrated.

But, people post questions for many reasons.  

Sometimes they are trying to self-learn and people like me are almost essential tools.

It is one of the reasons why fully supervised exams, with new questions, are so vital for assessing students of maths.

Many dishonest students will always cheat.  What is the difference between a student coming here, or going to a knowledgeable parent?

And all conscientious, honest students will look for extra help if what they are offered is of poor quality. 

On a slightly different vein:

What definitely annoys me is when I get asked to remove a question with answers, that is 3 or more years old, because it is an exam question.

How totally ridiculous is this.  Is the teacher or teaching facility too lazy to write new exams?  The question would be plastered across the internet in more than just this one site!  When I was teaching we had to write new exams every time. 

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I would like to learn. Why don't you tell me how to finish this question.  You know I am genuinely interested!

I am not cheating.  I just want to know.   Or do you only teach when you are paid to do so?

The question does not make sense.

anyway here is the pic so interpret what you want.

For what values of what???

Hint:

Let the pieces be

x, y-x   and  5-y    units long    

Now draw/graph a probability contour map.  

u=0

v=28

t=4

v=u+at

28=0+4a

a=7m/s^2

F=ma = 1000*7 = 7000 kg m/s^2

Nice work Dragan.

can't you just change your email? 

It goes upstream at 10km/hour for 3 km so that takes  0.3 of an hour

It goes downstream tat  18km/hour for 3km so that takes  1/6 of an hour

Total distance = 6km    total time = (18+10)minutes = 28/60 hour

ave speed =   \(6\div \frac{28}{60}=12\frac{6}{7}\;km/hour\)

Sorry guest answerers, I was correcting my answerer without seeing that you had already done so.

I did make a very careless error and I thank you for correcting it.

Hint:    Start by solving this to find n.

\( (x^{0.5})^n*(\frac{1}{x^2})^{10-n}=x^0\\\)

Thanks Sofsicle