We introduce a subclass of NP optimization problems which contains, e.g., Bin Covering and Bin Packing. For each problem in this subclass we prove that with probability tending to 1 as the number of input items tends to infinity, the problem is approximable up to any given constant factor $$P≤ft( \frac|Opt(I) - M(I)|\max { Opt(I),M(I)} ≥slant ε \right) ≤slant K\exp ( - hn)$$