<>=
## 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)
@
\begin{question}
According to a recent survey \Sexpr{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
\Sexpr{n} customers in front of you.
What is the probability (in percent) that \Sexpr{k} or more of the
other customers pay with their card?
\end{question}
\extype{num}
\exsolution{\Sexpr{fmt(sol, 2)}}
\exname{binomial v1}
\extol{0.01}