Math Problem Statement

Determine reasonable domains and ranges for functions describing practical scenarios like gas mileage, restaurant hours, car depreciation, and production cost.

Solution

Here are the solutions to the problems shown in the image:


58. A car's average gas mileage GG as a function of speed vv:

  • Reasonable domain for f(v)f(v):
    • The speed vv should be positive and within practical limits for a vehicle. Typically, 0<v1200 < v \leq 120 mph is a reasonable assumption, depending on context.

59. Restaurant open from 2 PM to 2 AM with maximum 200 clients:

(a) Reasonable domain for f(t)f(t):

  • The restaurant operates from 2 PM (t = 0) to 2 AM (t = 12). Thus, 0t120 \leq t \leq 12.

(b) Reasonable range for f(t)f(t):

  • The number of clients can range from 0 to 200. Thus, 0f(t)2000 \leq f(t) \leq 200.

60. Value V(a)=18,0003000aV(a) = 18,000 - 3000a for a car aa years old:

(a) Domain:

  • a0a \geq 0, since the car age cannot be negative. The upper limit depends on when the car value becomes zero:
    18,0003000a018,000 - 3000a \geq 0
    a6a \leq 6.
    So, 0a60 \leq a \leq 6.

(b) Range:

  • When a=0a = 0, V(0)=18,000V(0) = 18,000.
    When a=6a = 6, V(6)=0V(6) = 0.
    Therefore, 0V(a)18,0000 \leq V(a) \leq 18,000.

61. Cost C=2000+4xC = 2000 + 4x up to $10,000:

(a) Domain:

  • The production cost reaches the maximum limit of $10,000:
    2000+4x10,0002000 + 4x \leq 10,000
    4x80004x \leq 8000
    x2000x \leq 2000.
    Thus, 0x20000 \leq x \leq 2000.

(b) Range:

  • When x=0x = 0, C(0)=2000C(0) = 2000.
    When x=2000x = 2000, C(2000)=10,000C(2000) = 10,000.
    Therefore, 2000C10,0002000 \leq C \leq 10,000.

Do you need further clarification or detailed steps? Here are 5 related questions to expand the topic:

  1. How can domains and ranges change when additional constraints are added to a function?
  2. What factors could influence the realistic domain of gas mileage as a function of speed?
  3. Could a piecewise function model the restaurant problem more accurately?
  4. What happens to the value of a car after 6 years if depreciation isn't linear?
  5. How could we model costs that increase quadratically instead of linearly?

Tip: Always visualize the domain and range on a graph to better understand their practical implications!

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Math Problem Analysis

Mathematical Concepts

Function Domain
Function Range
Linear Functions
Piecewise Functions
Practical Applications of Functions

Formulas

V(a) = 18000 - 3000a
C = 2000 + 4x

Theorems

Properties of Linear Functions

Suitable Grade Level

Grades 9-12