20*5= 100 (points) 100-60=40 (points) 40/(5+3)=5 (topic) 20-5= 15 (topic)

Equation: Solution: Suppose he answers question X correctly.

5x-3﹙20-x﹚=60

5x-60+3x=60

8x-60+60=60+60

8x/8= 120/8

x= 15