Question

dolphin is 30 feet below the surface of the water. She rises 23 feet, sinks 17 feet, and finally rises another 27 feet. If there are no other changes, the dolphin is

Answer 1

Dolphin is 3 feet above the surface of the water.

Explanation:

Dolphin is 30 feet below the surface of the water, then its position on the vertical number line is -30.

• She rises 23 feet - add 23,
• sinks 17 feet - subtract 17,
• and finally rises another 27 feet - add 27.

Thus,

`-30+23-17+27\\ \\=(-30-17)+(23+27)\\ \\=-47+50\\ \\=3`

Dolphin is 3 feet above the surface of the water.