Answer:
n=12
Step-by-step explanation:
7n-18 =5n+6
+18 to both sides
7n=5n+24
-5n from both sides
2n=24
divide by 2
n=12
The tank can hold 31.8 gallons of water.
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 <==