Question

While Jackie was in Hawaii, she would dive for shells. One afternoon she dove −7.8 feet. Her next two dives were each 2 1/8 feet deeper than the dive before it. What were the depths of her second and third dives?

Dive 2: ? ft
Dive 3: ? ft

Answer 1

Dive 2: -9 37/40 feet

Dive 3: -12 1/20 feet

Explanation:

To solve this, we subtract 2 1/8 from -7.8 twice. First, convert -7.8 to a mixed number, that gets us -7 8/10. Now, we find the LCM of 8 and 10. That is 40. Now, we multiply 1/8 by 5/5 to get 5/40. Now, we multiply 8/10 by 4/4 to get 32/40. Now, we subtract 2 5/40 from -7 32/40. This gets us -9 37/40. That means Dive 2 was -9 37/40 feet. Now, we subtract 2 5/40 from -9 37/40. That gets us -12 2/40. We can simplify that to -12 1/20. That means Dive 3 was -12 1/20 feet.