Send a picture of it ok then i answer
Sea level is 0
robert dives 40 ft.....-40
he then rises 23 ft.....-40 + 23 = -17
he then dives 19 ft to meet Sam....-17 - 19 = -36
together they rise 31 ft...-36 + 31 = - 5
they are 5 ft below sea level <==
The answer is b because look at the angles
Its 4 by the way cause it is
15, 4000, and <span>0, 10,000.
to find the slope, subtract the y values over the x values
10000-400/0-15
6000/-15
divide.
</span>6000/-15 = -400
the slope is -400. Hope this helps! :D