If a server takes $20$ seconds to serve a customer on average and customers arrive every $20$ seconds on average. Both service time and customer arrivals have variabilities. what is the average waiting line length?

Group of answer choices

$2\mathrm{.}25$

$0$

Infinite

Can not be determined

More information is needed to determine which has a bigger change in average time in queue.

Reduction by more than $50\%$

No reduction

Reduction by less than $50\%$

$($Note that your answer should NOT include $"\%".$ For instance, if your answer is $20\%,$ then you should write $20$ in the blank.$)$

Round your answer to one decimal place.

Group of answer choices

$71\%$

Can not be determined

$43\%$

$60$