Temperature Decay

8
advanced-math

The temperature difference decreases by 10% every minute. If it starts at 50 degrees, what is the equation?

A

D(t)=50(0.10)tD(t) = 50(0.10)^t

B

D(t)=50(0.90)tD(t) = 50(0.90)^t

C

D(t)=50−10tD(t) = 50 - 10t

D

D(t)=50(1.10)tD(t) = 50(1.10)^t

Correct Answer: B

Choice B is the correct answer. Decrease of 10% means 90% remains.

  1. Identify Rate: r=0.10r = 0.10.
  2. Calculate Factor: b=1−0.10=0.90b = 1 - 0.10 = 0.90.
  3. Equation: D(t)=50(0.90)tD(t) = 50(0.90)^t.

💡 Strategic Tip: Always use what remains for the base.

Choice A is incorrect because 0.10 means losing 90%. Choice C is incorrect because it is linear.

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