Question

Difficulty: EasyInterpreting Linear Relationships in Context

A hiker begins a climb at an elevation of 1,2001,200 feet above sea level and climbs at a constant rate of 350350 feet per hour. The hiker's elevation, EE, in feet, tt hours after beginning the climb is given by the equation E=350t+1,200E = 350t + 1,200. Which of the following is the best interpretation of 350350 in this context?

  1. A
    The starting elevation, in feet, of the hiker
  2. The increase in the hiker's elevation, in feet, for each hour of climbingAnswer
  3. C
    The number of hours it takes the hiker to climb one foot
  4. D
    The total elevation, in feet, of the hiker after 350 hours of climbing

Answer

The increase in the hiker's elevation, in feet, for each hour of climbing
The coefficient of tt, which is 350350, represents the rate of change of the hiker's elevation with respect to time. Since elevation is measured in feet and time is measured in hours, this rate is 350350 feet per hour. Therefore, the value 350350 represents the increase in the hiker's elevation, in feet, for each hour of climbing.

Step-by-Step Solution

1
Identify the structure of the linear equation.
The equation E=350t+1,200E = 350t + 1,200 is in the slope-intercept form y=mx+by = mx + b, where m=350m = 350 is the slope and b=1,200b = 1,200 is the yy-intercept.
Linear equations in context have constant rates of change (slope) and starting values (yy-intercept).
2
Determine the meaning of the slope in context.
The slope 350350 represents the change in the dependent variable EE (elevation in feet) per unit change in the independent variable tt (time in hours).
The unit of the slope is the unit of the dependent variable divided by the unit of the independent variable, which is feet per hour.
3
Interpret the positive sign of the slope.
Since 350350 is positive, the elevation increases by 350350 feet for each hour of climbing.
A positive slope indicates a constant increase over time.

Key Concept

Interpreting slope in a linear context
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