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A mug of warm apple cider is gradually cooling. Its temperature in degrees Celsius (C)({}^\circ C) can be modeled with the expression 23+2420.014t23+24\cdot 2^{-0.014 t}, where the variable tt represents the time in minutes. Approximately how many minutes will it take for the temperature to reach 29C29{}^\circ C? (Round to the nearest minute.)

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Q. A mug of warm apple cider is gradually cooling. Its temperature in degrees Celsius (C)({}^\circ C) can be modeled with the expression 23+2420.014t23+24\cdot 2^{-0.014 t}, where the variable tt represents the time in minutes. Approximately how many minutes will it take for the temperature to reach 29C29{}^\circ C? (Round to the nearest minute.)
  1. Write Equation: Write down the given temperature model equation.\newlineWe have the temperature model equation: T(t)=23+24×20.014tT(t) = 23 + 24 \times 2^{-0.014t}, where T(t)T(t) is the temperature in degrees Celsius at time tt minutes.
  2. Set Equal to 2929: Set the temperature model equation equal to 2929 degrees Celsius to find the time tt when the temperature will be 2929 degrees Celsius.\newline29=23+24×2(0.014t)29 = 23 + 24 \times 2^{(-0.014t)}
  3. Subtract and Isolate: Subtract 2323 from both sides of the equation to isolate the exponential term.\newline2923=24×2(0.014t)29 - 23 = 24 \times 2^{(-0.014t)}\newline6=24×2(0.014t)6 = 24 \times 2^{(-0.014t)}
  4. Divide and Solve: Divide both sides of the equation by 2424 to solve for the exponential term.\newline624=2(0.014t)\frac{6}{24} = 2^{(-0.014t)}\newline14=2(0.014t)\frac{1}{4} = 2^{(-0.014t)}
  5. Take Logarithm: Take the logarithm of both sides of the equation to solve for tt. We will use the natural logarithm (ln) and the property that ln(ab)=bln(a)\ln(a^b) = b \cdot \ln(a).ln(14)=ln(20.014t)\ln(\frac{1}{4}) = \ln(2^{-0.014t})ln(14)=0.014tln(2)\ln(\frac{1}{4}) = -0.014t \cdot \ln(2)
  6. Divide and Calculate: Divide both sides of the equation by 0.014×ln(2)-0.014 \times \ln(2) to solve for tt.t=ln(14)0.014×ln(2)t = \frac{\ln(\frac{1}{4})}{-0.014 \times \ln(2)}
  7. Calculate t: Calculate the value of t using a calculator.\newlinetln(0.25)(0.014×ln(2))t \approx \frac{\ln(0.25)}{(-0.014 \times \ln(2))}\newlinet1.38629436112(0.014×0.69314718056)t \approx \frac{-1.38629436112}{(-0.014 \times 0.69314718056)}\newlinet1.38629436112(0.00970303639488)t \approx \frac{-1.38629436112}{(-0.00970303639488)}\newlinet142.857142857t \approx 142.857142857
  8. Round to Nearest Minute: Round the value of tt to the nearest minute.\newlinet143t \approx 143 minutes

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