Question preview
Wonky planes is a easy quant interview question on probability.
Join to unlock this question, detailed solutions, and our complete library of quant finance interview prep.
This is an easy probability problem that asks you to compare the failure rates of two aircraft designs using binomial reasoning. It appears frequently in quant interviews because it requires you to set up and solve a simple equation, then reason about whether one design dominates the other across all parameter values.
To approach it, calculate the probability that each plane type fails (given the failure probability of individual engines and the redundancy structure), then find the value of the engine failure rate at which the two probabilities are equal. Next, determine whether one plane is uniformly safer by comparing their failure curves across the full range of possible engine reliabilities.