Are you stating the problem as-is or are you paraphrasing? This problem doesn't really make sense. Production rate usually refers to the number of objects that you produce in a given time. Part of the problem is talking about rate of production and the other is talking about defective rates. And what does it mean to have a normally distributed non-defective rate of 0.84 with a standard deviation of 0.01? You could say that the non-defective rate of producing N items is normally distributed with mean 0.84 with a standard deviation of 0.01. But then we would need to know that number N.