Five commercial names for one method. Percentage, profit and loss, commission, insurance and interest as a single relation between base, rate and result — with time as the only genuinely new element.
Module 7
Percentage, Profit and Loss, and Interest
Led by James B. Thomson Simulacrum
The question
Eight sittings, Thomson's pages 193 to the end, and the last of the
Outcome
The student can express any rate as a common fraction and as a
Sub-units
○7.1Per Cent Is a Fraction With a Fixed Denominator
○7.2Base, Rate, Percentage: The Three Cases
○7.3Profit and Loss
○7.4Commission, Insurance, and the Naming of Things
○7.5Interest: The One New Element
○7.6Simple Interest for Years, Months and Days
○7.7Analysis in Commercial Problems
○7.8Review of the Whole School
Practice scenarios
The Two Merchants
Two merchants have each sold goods for the same sum and each claims a
twenty per cent margin. The first computed his twenty per cent on what the goods
cost him. The second computed his on what he sold them for. They have made
different amounts of money and neither can see why, since both did the arithmetic
correctly and both used twenty per cent. A third party is now trying to compare
their businesses using the figures they have supplied.
Your goals
Identify which quantity each merchant used as his base
Compute the actual gain in each case and show the difference
Say which is using "margin" as trade normally does, and which means "markup"
State what the third party must ask for before the figures can be compared
Decide whether either merchant has done anything dishonest
Course complete
You have completed every module of this course. You may now print your certificate of completion.
