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SEC2_BM · Applied mathematics · APPL.FINANCE.INTEREST

Simple and compound interest

Simple and compound interest

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Intuition

Understand first, compress later.

Mathematical models translate real situations into quantities, relationships and assumptions.

Switch representations
Timeline and duration8:15 → 12:05 = 3 h 50 min
7:008:009:0010:0011:0012:0013:0014:0015:0016:007:00get up8:15school starts12:05lunch15:30practiceWorking out the duration
scale: 7:00 to 16:00
eventthe interval being measuredhourly grid
The time axis is drawn to scale: equal stretches mean equal amounts of time. The gold band runs from 8:15 to 12:05 and lasts 3 h 50 min. A duration is a distance along the axis — you do not read it off a point, you step it out.
Formal view

You can simple and compound interest when you can recognise the underlying objects, select valid rules and check each step for equivalence or logical implication.

Why does it work?

This skill sits on a prerequisite network. If a step is unstable, repair the missing prerequisite instead of merely doing more items of the same type.