570*571
Hi everyone!
Please help me, finding the Variance of the following question:
As an advertising campaign, a chocolate factory places golden tickets in some of its candy bars, with the promise that a golden ticket is worth a trip through the chocolate factory, and all the chocolate you can eat for life. If the probability of finding a golden ticket is 1/571, find the mean and the variance of the number of candy bars you need to eat to find a ticket.
1. Mean: 571
2. Variance: ?
(I've already found Mean as 571 which is correct but I couldn't find the Variance...)