TL;DR
The Coupon Collector Problem: A canonical quantitative trading interview question at intermediate difficulty. Commonly asked at Jane Street, HRT, Optiver, Akuna Capital.
By Valenke Exam Prep Team·Last updated 2026-06-01
intermediateExpected Value & Variance
The Coupon Collector Problem
Asked at: Jane Street, HRT, Optiver, Akuna Capital
Problem
A cereal brand has different coupons, one included in each box. Each box contains a uniformly random coupon (independent). How many boxes do you need to buy, on average, to collect all coupons?
Compute the answer for .
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