Singapore Math - Ratio - using models to solve word problems

For more Singapore Math problems check out my channel at https://www.youtube.com/@inspiredLearning This video shows how to solve word problems using models. The topic discussed in this video is Ratio. In this type of problem you can verify what remains unchanged, and use it as a reference to solve the problem. The problem being solved in this video: The ratio of the number of boys to the number of girls in a ball was 3:2 at first. After 30 boys left the hall, the ratio became 2:3. How many boys were there in the hall at first?