Find the attached image , A detailed answer is given.
A,B,C,and F. If you can see A you can split then into fours, b,c,and f can all be split into half.
Well, f 80% is 60 marks, you'll need 20% more to make it full, so it would be 15 more marks, which would be 75 total marks = 100% =)
I hope I helped! =D
<span>Implement and follow up on the solution. Hope this helps :)</span>