notes:
c= Colin
s=Sara
g=Gordon
c=g+36 (1)
c : g
5 : 1
c/g=5
c=g*5 (2)
=> from statement (1) => g*5=g+36
5g-g=36
4g=36
g=36/4=9 g=9 sweets
=> from statement (2)=>c=5*9=45 c=45 sweets
s : g
2 : 1
=>s/g=2/1
=> s=2g
s=2*9 s=18 sweets
sum=c+s+g
sum=45+18+9=72 sweets
