I have a bag with red and blue marbles in it. At the moment, the ratio of blue marbles to red marbles is 5:4. I then add 4 blue marbles and 4 red marbles, and the ratio becomes 6:5. How many blue marbles were in the bag before I added more?

Logic Aug 18, 2018

#1**+2 **

B/R = 5/4.............................(1)

(B + 4)/(R + 4) = 6/5............(2)

From (1) above:

4B = 5R

B = 5R/4 sub this into (2) above

(5R/4 + 4)/(R + 4) =6/5, solve for R

**R = 16 - original number of red marbles B = 20 - original number of blue marbles.**

Guest Aug 18, 2018

edited by
Guest
Aug 18, 2018