```{r data generation, echo = FALSE, results = "hide"} ## success probability in percent (= pay with card) p <- sample(0:4, size = 1) ## number of attempts (= customers in queue) n <- sample(6:9, size = 1) ## minimum number of successes (= customers who pay with card) k <- sample(2:4, 1) ## compute the correct solution in percent sol <- 100 * pbinom(k - 1, size = n, prob = p/100, lower.tail = FALSE) ``` Question ======== According to a recent survey `r 100 - p` percent of all customers in grocery stores pay cash while the rest use their credit or cash card. You are currently waiting in the queue at the checkout of a grocery story with `r n` customers in front of you. What is the probability (in percent) that `r k` or more of the other customers pay with their card? Meta-information ================ extype: num exsolution: `r fmt(sol, 2)` exname: binomial v1 extol: 0.01