Laurie was scuba diving. Each time she dove 5 feet deeper, she would stop and clear her ears. Each time that this totaled 20 feet deeper, she would stop and check her instruments to make sure they were working properly. After Laurie had checked her instruments 3 times, she was at her maximum depth. Which expression best represents Laurie’s maximum depth?
Answer
A
negative 4 times negative 5 times negative 3
B
negative 5 times 20 times 3
C
4 times negative 5 times 3
D
negative 5 times negative 20 times negative 3
Explanation
Each instrument check follows a 20-foot descent, which is four 5-foot intervals. Each interval downward is represented by −5 feet, and Laurie checked her instruments 3 times, so the expression is 4 × (−5) × 3 = −60 feet. Choice C correctly represents those intervals and checks; the negative sign indicates depth below the starting point.
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