Asled of mass m is being pulled horizontally by a constant horizontal force of magnitude f. the coefficient of kinetic friction is μk. during time interval t, the sled moves a distance s, starting from rest.
find the average power pavg created by the force f.

I'll bite:

-- Since the sled's mass is 'm', its weight is 'mg'.

-- Since the coefficient of kinetic friction is μk, the force acting opposite to the direction it's sliding is    (μk) times (mg) .

-- If the pulling force is constant 'F', then the horizontal forces on the sled
are 'F' forward and (μk · mg) backwards.

-- The net force on the sled is  (F - μk·mg).
(I regret the visual appearance that's beginning to emerge,
but let's forge onward.)

-- The sled's horizontal acceleration is  (net force) / (mass) = (F - μk·mg) / m.
This could be simplified, but let's not just yet.

-- Starting from rest, the sled moves a distance 's' during time 't'.
We know that  s = 1/2 a t² , and we know what 'a' is.  So we can write

           s = (1/2 t²)  (F - μk·mg) / m    .

Now we have the distance, and the constant force.
The total work is (Force x distance), and the power is (Work / time).
Let's put it together and see how ugly it becomes.  Maybe THEN
it can be simplified.

Work = (Force x distance) =  F x  (1/2 t²)  (F - μk·mg) / m
 
Power = (Work / time) =    F (t/2) (F - μk·mg) / m

Unless I can come up with something a lot simpler, that's the answer.

To simplify and beautify, make the partial fractions out of the
2nd parentheses:
                                    F (t/2) (F/m - μk·m)

I think that's about as far as you can go.  I tried some other presentations,
and didn't find anything that's much simpler.

Five points,ehhh ?