```{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
