Okay, so to find the total amount of time you need to add the two fractions.
So, to add 3/4 + 1/5 you first need to make the denominators the same:
1) making the same denominator
3/4 x 5/5 = 15/20
And
1/5 x 4/4 = 4/20
When you add these you get 19/20, which cannot be simplified as the numbers 19 and 20 have no common factors.