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5. A diver searches for a sunken treasure that is 97.2 feet below the surface. What is the diver’s elevation when he is 2/3

of the way down?(1 point)
Responses

-64.8 ft
-64.8 ft

-145.8 ft
-145.8 ft

-32.4 ft
-32.4 ft

-48.5 ft

5 answers

To determine the diver's elevation when he is 2/3 of the way down to the treasure, we first need to find out how far down that is.

  1. Calculate 2/3 of the total depth of the treasure: \[ \text{Depth} = \frac{2}{3} \times 97.2 \text{ ft} = 64.8 \text{ ft} \]

  2. Since the treasure is below the surface, we take the total depth of 97.2 ft into account. The elevation of the diver 2/3 of the way down can be found by subtracting 64.8 ft from the surface elevation (0 ft): \[ \text{Diver's elevation} = 0 - 64.8 \text{ ft} = -64.8 \text{ ft} \]

Thus, the diver’s elevation when he is 2/3 of the way down is -64.8 ft.

6. A diver descends at a rate of 8 m/min. Which expression CANNOT be used to find her depth after 5 minutes?(1 point)
Responses

−8(5)
negative 8 times 5

−8+(−8)+(−8)+(−8)+(−8)
negative 8 plus negative 8 plus negative 8 plus negative 8 plus negative 8

−8−8−8−8−8
negative 8 minus 8 minus 8 minus 8 minus 8

−8/5

To determine which expression cannot be used to find the diver's depth after 5 minutes, let's evaluate each option:

  1. \(-8(5)\)

    • This expression calculates the depth correctly as it represents descending at a rate of 8 m/min multiplied by 5 minutes:
      \(-8(5) = -40\).

  2. \(-8 + (-8) + (-8) + (-8) + (-8)\)

    • This expression sums up the depth over 5 minutes:
      \(-8 + (-8) + (-8) + (-8) + (-8) = -40\), also correct in calculating depth.

  3. \(-8 - 8 - 8 - 8 - 8\)

    • This expression also sums for 5 minutes but uses subtraction repeatedly:
      \(-8 - 8 - 8 - 8 - 8 = -40\), which is correct as well.

  4. \(-8/5\)

    • This expression does not correctly reflect the depth after 5 minutes. Instead, it calculates the rate of descent per minute, not the total depth after 5 minutes:
      \(-8/5 = -1.6\), which does not represent the total depth after 5 minutes.

Therefore, the expression that CANNOT be used to find her depth after 5 minutes is \(-8/5\).

7. In September, a sporting goods store offers a kayak for $378. Over the next four months, the store reduced the price of the kayak $15 each month. What is the price of the kayak at the end of four months?(1 point)
Responses

$363
$363

$438
$438

$318
$318

$228

To find the price of the kayak at the end of four months, we need to calculate the total reduction in price over that period and then subtract it from the original price.

  1. Initial Price of the Kayak: $378

  2. Monthly Price Reduction: $15

  3. Total Reduction over 4 Months: \[ \text{Total Reduction} = 4 \text{ months} \times 15 \text{ dollars/month} = 60 \text{ dollars} \]

  4. Price of the Kayak after 4 Months: \[ \text{Final Price} = \text{Initial Price} - \text{Total Reduction} = 378 - 60 = 318 \text{ dollars} \]

Therefore, the price of the kayak at the end of four months is $318.