Students from a university in Shanghai also took part in the final college entrance examination mathematics. A total of 150 people in this major passed the exam, with a passing rate of 90%. Make-up exams are required. The passing rate is 90%, and those who fail150x (1-90%) =15 people.

The make-up exam failed 20%, 15x20%=3 people, and failed again. The rest 12 people passed the make-up exam.

Those three idiots failed in the end. So the final pass rate is (150-3)/150 x100% = 98%.

Comprehensive formula calculation:

[ 150- 150 x( 1-90%)x20 %]/ 150 x 100% = 98%

Answer: The final pass rate is 98%.