Question 1159591
F+S+T=20
5F+3S+1T=68
but S=F+T
so the first may be written as
2F+2T=20
and the second as 
8F+4T=68
-4F-4T=-40 multiplying the top by -2
4F=28
F=7  first places and 35 points
Now there is S+T=13
and 3S+1T=33 (points left)
and -S-T=-13
2S=20
S=10 second places 
T=3 third places 
!st place--7
2nd place-10
3rd place--3