Answer:
6 tulips
Explanation:
First, we have to simply the ratio. The ratio for pansies to tulips would be 15:18, then simplifying it would make it 5:6 because the common factor is 3. 15 divided by 3 is 5 and 18 divided by 3 is 6. If you add 5 more pansies, it would equal 20 in total. Add 6 tulips because 6 plus 18 is 24. 20 divided by 4 is 5 and 24 divided by 4 is 6. That gives us a ratio of 5:6, which is the same from before. Therefore, you should add 6 tulips if 5 more pansies were added.