What decimal of an hour is a second?

If $x\%$ of $y$ is equal to $z$ then what percentage of $z$ is $x$?

One-fifth of a number is equal to $(\frac{5}{8})^{th}$ of another number. If 35 is added to the first number, it becomes four times the second number. Find the second number.

In a factory there are three types of machines b1, b2, and b3 which produces 20%, 15%, and 32% of the total products respectively. Further, machines b1, b2, and b3 which produces 3%, 7%, and 2% defective products respectively. Find the percentage of non-defective products?