Question 810555
Let us dissect the question carefully to fully comprehend the implications involved and then, we can easily find our answer.

Now, let's look at it practically;

If it takes 3 men 41minutes to paint 5 walls, how many minutes do you think it will take only one man (working at the same rate)?

Thrice the time of course!
That means;
It takes 1 man {{{(41 * 60) * 3}}}seconds to paint those 5 walls.
(Please note I converted the time to seconds for ease in division operations.

It takes 1 man {{{7380}}}seconds to paint 5 walls.

GOOD! We're doing well.

Now, at the same rate, how long will it take to paint one wall?

You thought right! Just one-fifth of the time for 5 walls.

That means,
It will take 1 man {{{7380*(1/5)}}}seconds to paint 1 wall.
and that is
={{{1476}}}seconds for a single wall.


Good! Now we know how long it will take for ONE man to paint ONE wall.

How long then will it take for ONE man to paint 8 walls?

Right - 8 times the time taken for a single wall!

i.e. It will take {{{8 * 1476}}}seconds to paint 8 walls.
={{{11808}}}seconds for 8 walls.


DON'T GIVE UP, WE'RE ALMOST THERE.

It takes 1 man 11,808 seconds to paint 8 walls, how long then will it take 8 men to do the same job?

one-eight of the time!

So, it'll take 8 men {{{(1/8) * 11808}}}seconds to paint 8 walls.
Therefore, it'll take 8 men 1476seconds to paint 8 walls.

Remember, we were asked to leave our answer in minutes (to the nearest minute actually).

1476 seconds = 24 minutes and 36 seconds.

36 seconds is just over the half-mark, friend; so we're left with 25 minutes of work time for our painter-friends.


SO, IT'LL TAKE OUR FRIENDS AT BERGER PAINTS 25 MINUTES TO DO THE JOB.


Understood?
(PS: we always assume they all work at the same rate - say, they're programed machines.)