Question

A diver descends $20$ feet underwater from a boat on the surface of the lake. He then rose $12$ feet and descends another $18$ feet. Find his final position.

• A. 13 feet below the surface of the lake.
• B. 17 feet below the surface of the lake.
• C. 21 feet below the surface of the lake.
• D. 26 feet below the surface of the lake.

Answer 1

The correct option is D 26 feet below the surface of the lake.

Let the initial position of the diver be 0.
Descend of $20$ feet --------$(-20)$ [ from O to A]
Then rises $12$ feet -------- $(+12)$ [ from A to B]
Descend of $18$ feet ------- $(-18)$ [ from B to C]
Final position of the diver = $(-20+12-18)$ feet $=-26$ feet
Therefore, the man is now at $26$ feet below the surface of the lake.

Here, red colour represents moving down and green colour represents moving up.