There would be 32 light colors. To get 32 you divide 20 by 5 to see how much you went up bu. 20 divided by 5 is 4. Then you would do 8 times 4 which is 32. Another way you can solve it is to start with the ratio 5/8. (5 dark colors for every 8 light colors.) Then to get another equivalent ratio but higher, you just multiply both by two which would be 10/16. Since you are not to 20 dark colors yet multiply by 2 again. 20/32. Now you have 20 dark colors, so you would have 32 light colors.
