Ascuba diver dives to a depth of 50 feet, sinks 12 feet, then rises 20 feet. what is the diver's final position relative to sea level?

We can use a number line to help us solve, but I guess "visualizing" it with a vertical number line works too. 

We start at the point 0. We go down to the point -50, after the diver dives down to a depth of 50 feet. "Sink" is to go down, so we go down to -62 because -50-12=-62. "Rise" is to go up, so we go up to -42 because -62+20=-42.

The diver's final position relative to sea level would be at 42 feet.

  B.  0 ≤ x ≤ 6

Step-by-step explanation:

The horizontal grid lines are 10 °C apart, so 45 °C corresponds to a vertical position halfway between the 4th grid line and the one marked 50.

The graph intersects that position at the 2nd vertical grid line. The vertical grid lines are 3 minutes apart, so the 2nd grid line represents 6 minutes.

If Peter conducted the experiment from its start until the temperature reached 45 °C, he conducted it over a period of 0 to 6 minutes, inclusive:

  0 ≤ x ≤ 6