M4apt

After investing some time in the preparation, it's not uncommon to realize that it would be better if we make our own notes which we can refer while revising these topics before the exam. In order to make this procedure simple, I have come up with this post. 1) Ratios and proportions: If a certain amount N is divided among A, B in a ratio a:b then A's share is a/(a+b) * N and B's share is b/(a+b) *N If A:B = a:b and B:C = c:d then A:C = a*c : b*d If A:B = p:q, B:C = r:s, C:D = t:u then A:D = A/D = (A/B) * (B/C) * (C/D)    If a quantity is increased by a/b then the new content becomes (a+b)/b If a quantity is decreased by a/b then the new content becomes (b-a)/b To reduce your computations, it is always recommended to remember these values in terms of percentages 1/1 = 100 % 1/2 = 50 % 1/3 = 33.33 %   1/4 = 25 % 1/5 = 20 % 1/6 = 16.66 % 1/7 = 14.28 %       1/13 = 7.6% 1/8 = 12.25 %       1/12 = 8.33% 1/9 = 11.11 %       1/11 = 9.09% 1/10 = 10 % Prop