2021-010

A crack appeared in a container and the liquid in it began to leak. At instant \( t \ge 0 \), a total of \( 10t - \sqrt{t} \) units of the liquid will have leaked. What is the flow rate \( r \) of the liquid through the crack at instant \( t = 100 \) ?

1. \( r = 99/2 \)
2. \( r = 99/20 \)
3. \( r = 199/2 \)
4. \( r = 199/20 \)
5. None of the above

Original idea by: Bruno Almêda