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1.5 Exponentials and logarithms

1.5 Exponentials and logarithms

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Question 19

The temperature of water in a kettle is modelled using the equation T=75e−kt+25T = 75e^{-kt} + 25T=75e−kt+25

a.

Explain what the 25 represents in the equation T=75e−kt+25T = 75e^{-kt} + 25T=75e−kt+25

[1]
b.

When the kettle is turned off the rate of decrease of the water temperature is 20∘C20^{\circ}\text{C}20∘C per minute. 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

[3]
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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