Current location - Training Enrollment Network - Mathematics courses - The correct rate of smiling and doing math problems is 95%. How many questions did you do wrong?
The correct rate of smiling and doing math problems is 95%. How many questions did you do wrong?
95% are right, then (1-95%) = 5% are wrong.

1 channel → 5%

X channel → 100%

x = 1× 100%÷5% = 1÷5% = 1× 100/5 = 1×20 = 20

So a * * * did 20 questions.