First, let's break down the expression:

3.5 - 1 1/5 * 4.5

To subtract mixed numbers, we need to convert the mixed number 1 1/5 to an improper fraction.

1 1/5 = (5*1 + 1)/5 = 6/5

Now we can substitute this back into the expression:

3.5 - 6/5 * 4.5

Next, we'll multiply the fraction by 4.5:

6/5 * 4.5 = 27/5

Now we have:

3.5 - 27/5

To subtract these fractions, we need a common denominator:

3.5 = 17.5/5

Now we can subtract:

17.5/5 - 27/5 = (17.5 - 27)/5 = -9.5/5 = -1.9

So the expression simplifies to -1.9.

Now we'll continue with the remainder of the expression:

-1.9 + 0.19 + 50

Next, we add the decimal numbers:

-1.9 + 0.19 = -1.71

Finally, we add the result to 50:

-1.71 + 50 = 48.29

Therefore, the final result of the expression is 48.29.