Constant Rate Math Example 3

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Example 3

easy
A plumber charges a \50flatfeeplus flat fee plus \7575 per hour. Write C(h)C(h) and find the cost for 33 hours. At what hour does the cost reach \275$?

Solution

  1. 1
    C(h)=75h+50C(h) = 75h + 50. For h=3h=3: C(3) = 225+50 = \275$.
  2. 2
    Set C(h)=275C(h)=275: 75h+50=275โ‡’75h=225โ‡’h=375h+50=275 \Rightarrow 75h=225 \Rightarrow h=3. The cost reaches \275atexactly at exactly 3$ hours.

Answer

C(h)=75h+50C(h) = 75h+50; C(3) = \275;at; at h = 3$ hours
A flat fee plus a per-unit charge creates a linear function with the rate as slope and the flat fee as yy-intercept. Here the slope 7575 represents the constant rate (cost per hour).

About Constant Rate

A constant rate of change means the output increases (or decreases) by the same fixed amount for every unit increase in the input โ€” the hallmark of a linear function.

Learn more about Constant Rate โ†’

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