Question 63
The relay in a race - in a relay competition, in which each team has two athletes, each athlete runs $21~\mathrm{km}$ and the second athlete only starts the race when the first athlete finishes his part and passes him the baton. The record for this competition is 2 hours and 48 minutes. In João and Carlos' team, João starts the race and runs his part with a speed of $12~\mathrm{km}/\mathrm{h}$. To beat the record, what should be Carlos' speed?