Let's assume that the number of electronic organ groups is X, the ratio of model group to electronic organ group is 5: 7, and the ratio of electronic organ group to math group is 5: 7. There are 5/7*x in the model airplane group, 7/5*x in the math group, and 3 interest groups in an experimental primary school 198.

X+5/7*x+7/5*x= 198 gives x=

Is there anything wrong with this question? The solution of x is not an integer.