The percentage is the time. 75% is the time which Jhon takes to fill the tank, 100% is the total time. For example if 100% is one year, 50% are six months. But in this circumstance it does not interest to me, 100% should be an year or a minute.

I have to pay them in according to the effort which they do during the job. In this case I think that this effort should be the speed of filling. So I tried to do the following:

TOTAL time 100%

Mark 2L in 75% of the time (t) ==> 1% t : x L = 75% t : 2 L => 0.02 L in 1% of the time

Jhon 3L in 60% of the time (t) ==> 1% t : x L = 60% t : 3 L => 0.05 L in 1% of the time

Victor 2L in 33% of the time (t) ==> 1% t : x L = 33% t : 2 L => 0.06 L in 1% of the time

0.02L + 0.05L + 0.06L = 0.13 L TOT at 1% of the time

Mark => 0.02 L : 0.13 TOT L = x : 100 => 15.4 %

Jhon => 0.05 L : 0.13 TOT L = x : 100 => 38.5 %

Victor => 0.05 L : 0.13 TOT L = x : 100 => 46.1 %

So if I've 100$, I give 46.1$ to Victor, 38.5$ to Jhon and 15.4$ to Mark.

Is it correct?

I'd think you'd want to pay for the

*work done*, not for speed, because that is what benefits you. If you pay each of them the same for the same number of liters, then the one who is faster is getting more

*per hour*, which is appropriate.

I also think it's confusing to measure time in percent rather than just in days or years or whatever, since you are talking about a fixed time, not about a percentage of the total time they take (despite your use of the word "total").

I can't make much sense of your calculation. Let's take it this way:

Suppose Mark transports 2 liters in 0.75 hour, John 3 liters in 0.60 hour, and Victor 2 liters in 0.3 hour. Since the total amount filled is 2+3+2 = 7 liters, I'd pay them, respectively, 2/7, 3/7, and 2/7 of the $100. It makes sense for John to get more, because he has done more for you.

Their rates are:

Mark: 2/0.75 = 2.66 liters/hour

John: 3/0.60 = 5 liters/hour

Victor: 2/0.33 = 6 liters/hour

If you paid them in proportion to their rates (which is true of the amounts you calculated), you would pay Victor more than John, though he accomplished less and spent less time working for you. Why?

Or do you really want to somehow combine rate

*and* work done, giving a bonus for speed?