Say an 85 IQ laborer has a failure rate of 5% for any one step, while a 100 IQ laborer has a failure rate of 1%. This does not sound like that big or cardinal of a difference. But repeated ten times, some 40% of the duller worker’s production ends up being a dud, compared to only 10% of the brighter worker’s.

i know that the way you get "some 40%" of the duds is 1-(0.95^10) but how would you go about getting the 40% just using the 5% failure rate and the fact that it was done 10 times