We know that he takes 10 quizzes per 2 weeks
That means we need to add 10+10+10+10=40 quizzes and 2+2+2+2=8 weeks
But were not done! Half of 10 = 5 so that means it will take 1 week to take 5 quizzes
8+1=9
It will take him 9 weeks to take 45 quizzes
Hope this helped!