FeaturesHow It WorksFor ParentsPricingContactLog inStart free — no credit card needed →

General Mathematics · Unit 3 · Growth and decay in sequences · The geometric sequence

Display the terms of a geometric sequence in both tabular and graphical form and demonstrate that geometric sequences can be used to model exponential growth and decay in discrete situations.

Practise this objective

AI-marked practice questions tied to QCAA mark schemes for this exact LO. Free to start.

Start free practice

Practice questions for this objective

Full questions, answers and worked solutions unlock when you start a free practice session.

Question 1

A wildlife park releases a population of endangered birds. The population at the end of each year follows a geometric sequence with first term \(a = 120\) birds and common ratio \(r = 1.25\). (a) Complete the table showing the population for Years 0 through 4. Round all values to the nearest whole number. (1 mark) (b) Display this data in a scatterplot with labelled axes, using Year as the independent variable. (2 marks)

Worked answer
🔒 Start free to see full answer
Question 2

A colony of bacteria triples every hour. The initial population at hour 0 is 200 bacteria. A table showing the first three hours is provided. Determine the population of bacteria at hour 4.

Worked answer
🔒 Start free to see full answer
Question 3

The resale value of a motorcycle shows geometric decay. Determine the resale value four years after purchase.

Worked answer
🔒 Start free to see full answer
Question 4

A mobile phone depreciates by 15% each year. Its initial value is $1,200. (a) Complete the table showing the phone's value at the end of each year for the first four years. (1 mark) (b) Display this data on a scatterplot with labelled axes, plotting the phone's value against the year number. (2 marks)

Worked answer
🔒 Start free to see full answer
Unlock all 4 answers — free

More in The geometric sequence

Next →
Use geometric sequences to model and analyse practical situations involving geometric growth and decay (use of logarithms not required), e.g. modelling the growth of a bacterial population that doubles in size each hour, calculating the value of an item using the diminishing-value method of depreciation.
All LOs in The geometric sequenceBack to full General Mathematics syllabus