3.53 Usually, two mechanisms are involved in performing a certain task simultaneously. The productivity of these mechanisms is not the same, and when working together, they complete the task in 30 hours. Once, the joint operation of the two mechanisms lasted only 6 hours, after which the first mechanism was stopped, and the second mechanism completed the remaining part of the task in 40 hours. How long would it take for each mechanism to complete the same task individually, working at its inherent productivity?
3.53 Let's accept the entire volume of work as a unit. Let the first mechanism complete the task in $x$ hours, and the second in $y$ hours. Since when working together, the capacities (productivities) add up, we have the system of equations

$$
\left\{\begin{array}{l}
\frac{1}{x}+\frac{1}{y}=\frac{1}{30} \\
1-6\left(\frac{1}{x}+\frac{1}{y}\right)=\frac{40}{y}
\end{array}\right.
$$

Solving it, we find $x=75$ hours, $y=50$ hours.

Answer: $\quad z a ~ 75$ and 50 hours.