What is the formula to determine the number to add to ratio to increase the percentage. For example.. I have 1000 marbles. 700 blue and 300 red(30%). how many red marbles to I add to get 40% red marbles. The number in this case is 167. 467/1167 = .40
by 
alex
ANSWERS: 2
-
eh...?? just add 100 marbles... oh yeah, that wopn't work...getcha now....! eh...give up. Started from here, but got messy: A/(A+B) = C% (A+x)/((A+x)+B) = C+y% ABC & y are all known x = ((C+y%)*(A+B+x))-A x = A*(C+y%) + B*(C+y%) +x*(C+y%) for clarity - in your example *A=300, B=700, C = 30% x = the unknown, and y is the % increase = 10% Hope that helps.... :-S
-
Suppose you have N marbles and a percentage P. You add n red marbles and want to get a percentage Q. Old red marbles = (P/100) N New red marbles = ((P/100) N) + n New number of marbles = N + n New percentage = Q = 100 (((P/100) N) + n) / (N + n) Solve for n: (Q/100) (N + n) = ((P/100) N) + n Q (N + n) = (P N) + 100 n n = (Q - P) N / (100 - Q) Test, in your case: 10 * 1000 / 60 = 166.7 To answer your question, write down exactly the operations you got to get 167. Now replace the numbers with letters and do exactly the same steps you did the first time. You end up with the formula.
RELATED QUESTIONS
Copyright 2023, Wired Ivy, LLC