x-x/ 10=98-x-3
The solution is x=50.
So * * * there are 50 boys and 48 girls.
Analysis: Total number of boys+total number of girls =98.
Total number of boys-number of boys participating in the competition = total number of girls-number of girls participating in the competition (3)
Suggestion: It is very useful to do this kind of problems mainly by grasping the equivalence relationship!