A pot of piping hot stew has been removed from the stove and left to cool.The relationship between the elapsed time, m, in minutes, since the stew was removed from the stove, and the temperature of the stew, T(m), measured in ∘C, is modeled by the following function.T(m)=20+50⋅10−0.04mHow many minutes will it take for the stew to cool to a temperature of 30∘C ?Round your answer, if necessary, to the nearest hundredth.minutes
Q. A pot of piping hot stew has been removed from the stove and left to cool.The relationship between the elapsed time, m, in minutes, since the stew was removed from the stove, and the temperature of the stew, T(m), measured in ∘C, is modeled by the following function.T(m)=20+50⋅10−0.04mHow many minutes will it take for the stew to cool to a temperature of 30∘C ?Round your answer, if necessary, to the nearest hundredth.minutes
Set up the equation: Understand the problem and set up the equation.We need to find the time m when the temperature T(m) is equal to 30∘C. The given function is T(m)=20+50×10(−0.04m). We set this equal to 30∘C to solve for m.30=20+50×10(−0.04m)
Isolate exponential part: Isolate the exponential part of the equation.Subtract 20 from both sides to isolate the term with the exponent on one side.30−20=50×10(−0.04m)10=50×10(−0.04m)
Divide to solve exponential term: Divide both sides by 50 to solve for the exponential term.5010=10(−0.04m)0.2=10(−0.04m)
Take logarithm to solve for m: Take the logarithm of both sides to solve for m.We use the property that log(ab)=b⋅log(a) to solve for m.log(0.2)=log(10−0.04m)log(0.2)=−0.04m⋅log(10)Since log(10) is 1, we can simplify this to:log(0.2)=−0.04m
Solve for m: Solve for m by dividing both sides by −0.04. m=−0.04log(0.2) Now we calculate the value of m using a calculator. m≈−0.04log(0.2) m≈−0.04−0.69897 m≈17.47425
Round to nearest hundredth: Round the answer to the nearest hundredth.m≈17.47
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