Question

2 times in 60 seconds how many seconds went by before the manatee surface the first time if it held its breath for the same rate

Answer 1

It took a breath every 30 seconds.
Assuming that the breath instantly gives enough air, and then the manatee goes right back under, then the manatee goes under every;
$\frac{60sec}{2\ breaths}=\frac{30 sec}{breath}$
Thus, the manatee holds its breath for 30 seconds.