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1.5 Exponentials and logarithms

1.5 Exponentials and logarithms

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Question 6
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The temperature of water in a kettle is modelled using the formula T=75e−kt+22T = 75e^{-kt} + 22T=75e−kt+22 Where T T\,T is the temperature t t\,t minutes after the kettle is turned off and k k\,k is a positive constant.

a.

Find the rate of change of the temperature in terms of kkk

[2]
b.

After 5 minutes the temperature of the water is 70∘C70^{\circ}\text{C}70∘C. Find the value of kkk

[3]
c.

Find how many minutes it takes for the water to cool to 55∘C55^{\circ}\text{C}55∘C

[4]
Markscheme

1.5 Exponentials and logarithms Questions

  1. A Level
  2. /Maths
  3. /1.5 Exponentials and logarithms

77 exam-style questions on CCEA A Level Maths 1.5 Exponentials and logarithms, covering 1.5.1 Exponentials and logarithms, 1.5.2 Exponentials and logarithms, 1.5.3 Exponentials and logarithms, 1.5.4 Exponentials and logarithms, 1.5.5 Exponentials and logarithms, 1.5.6 Exponentials and logarithms, 1.5.7 Exponentials and logarithms, and 1.5.8 Exponentials and logarithms. Each one has a worked solution and a mark scheme showing where the marks go.

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