I don't know if you've learnt this, but there's something called the KFC rule (you use it when dividing fractions), so k basically stands for keep (so you keep the first fraction), f stands for flip (so you flip the second fraction) and c stand for change (you change the division sign to a multiplication sign)
So you get
5/20*11/5
55/100
which is 11/20
so, an answer of 11/20 would make Quintin correct
The supplement of 30° is the angle that when added to 30° forms a straight angle (180° ).