Assuming that "forth" is your attempt to spell fourths, the answer is eleven and two fifths.
1
They add to: 4 and 1/5
I think it's 1 and 2/5
2 and 6/5 or 3 and 1/5
too hard
3
2/5 + 1/5 = 3/5
It is: 1 and a 1/2 plus 3/5 = 2 and 1/10 or 2.1
4/5+ 2/5 = 6/5 = 1/1/5 or 1.2
1 and 1/2
17/30