All the children of a class were asked to choose between the cartoon shows 'Shin Chan' and 'Tom and Jerry'. The ratio of children who selected the cartoon 'Shin Chan' to those who selected the cartoon 'Tom and Jerry', was 3:1. If 45 kids selected 'Shin Chan', how many students are there in the class totally?

There were 60 kids in class.

Step-by-step explanation:

Since the kids had two choices and the ratio between them was for every 3 children that selected "Shin Chan" only 1 selected "Tom and Jerry", then in order to calculate the number of children in the class if 45 kids selected "Shin Chan", we first need to calculate the number of children that selected the other option. To do that we divide the number by 3. We have:

children (Tom and Jerry) = children (Shin Chan) / 3

children (Tom and Jerry) = 45/3 = 15

Therefore the number of children in the class is:

children (class) = children (Tom and Jerry) + children (Shin Chan)

children (class) = 15 + 45 = 60

There were 60 kids in class.