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1.7 D: Sequences and series

1.7 D: Sequences and series

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Question 80

In this question you must show detailed reasoning.

A chemical reactor is being commissioned over a 12-day period. During this period, a technician performs a primary catalyst injection every morning and a secondary maintenance flush every afternoon.

  • On the morning of day 1, the catalyst injection is 15 liters.
  • On the morning of day 12, the catalyst injection is 81 liters.

The technician considers two different commissioning protocols for the morning injections.

In Protocol A, the volume of catalyst injected each morning increases by the same constant amount each day.

a.

Calculate the volume of catalyst injected on the morning of day 8 under Protocol A. (3)

[3]
b.

In Protocol B, the volume of catalyst injected each morning increases by a constant percentage each day.

Calculate the volume of catalyst injected on the morning of day 8 under Protocol B. Give your answer in liters to one decimal place. (3)

[3]
c.

Additionally, a fixed volume, vvv liters, is used for the maintenance flush every afternoon for the entire 12-day period. Given that:

  • vvv is an integer
  • the total volume of liquid (catalyst and flush) used over the 12 days must not exceed 1100 liters.

(i) Determine the maximum possible value of vvv if Protocol A is used. (ii) Determine the maximum possible value of vvv if Protocol B is used. (5)

[5]
Markscheme

1.7 D: Sequences and series Questions

  1. A Level
  2. /Maths
  3. /1.7 D: Sequences and series

308 exam-style questions on AQA A Level Maths 1.7 D: Sequences and series, covering 1.7.1 Binomial expansion, 1.7.2 Types of sequence (A-level only), 1.7.3 Sigma notation (A-level only), 1.7.4 Arithmetic sequences and series (A-level only), 1.7.5 Geometric sequences and series (A-level only), and 1.7.6 Sequences and series in modelling (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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