Roger is a wildlife researcher who has been hired to study and track the population of bears in a national park. In Year 1 of the study, Roger determines that the park is home to x

bears. In Year 2, the population has increased to x+10
bears, and in Year 3, the population has increased to 2(x+10)
bears.
Use the Distributive Property to rewrite the bear population in Year 3 without needing to use parentheses.
The total number of bears in the park during Year 2 is 42. Write and solve a linear equation to determine how many bears were in the park during Year 1.
The total number of bears in the park during Year 3 is 50. Write and solve a linear equation to determine how many bears were in the park during Year 1. Note that this answer will not be the same as the answer you got in part b
.
During Year 4, bad weather keeps Roger from finding the exact number of bears in the park. However, he knows that y+5>38
, where y
is the number of bears in the park during Year 4. Solve the inequality, and give three possible values for y
.

1 answer

Step 1: Rewrite the Year 3 Population Using the Distributive Property

The population of bears in Year 3 is given as \( 2(x + 10) \).

Using the Distributive Property: \[ 2(x + 10) = 2x + 20. \]

So, the bear population in Year 3 without parentheses is \( 2x + 20 \).


Step 2: Determine the Number of Bears in Year 1 Based on Year 2 Population

We know that the total number of bears in Year 2 is 42: \[ x + 10 = 42. \]

To solve for \( x \): \[ x = 42 - 10, \] \[ x = 32. \]

So, the number of bears in Year 1 is 32.


Step 3: Determine the Number of Bears in Year 1 Based on Year 3 Population

We know that the total number of bears in Year 3 is 50: \[ 2(x + 10) = 50. \]

First, we can simplify the equation: \[ 2x + 20 = 50. \]

Now, solving for \( x \): \[ 2x = 50 - 20, \] \[ 2x = 30, \] \[ x = 15. \]

So, the number of bears in Year 1 is 15.


Step 4: Solve the Inequality for Year 4

We know that \( y + 5 > 38 \).

To solve for \( y \): \[ y > 38 - 5, \] \[ y > 33. \]

Possible values for \( y \) can be any numbers greater than 33. Therefore, three possible values for \( y \) could be:

  • 34
  • 35
  • 36

Thus, values for \( y \) could be \( 34, 35, \) or \( 36 \).