Mathematics for IGCSE & O level - Proportion (Section 2 - No. 3)
Which of the following statements is an example of a joint variation?
The time taken to travel a certain distance is inversely proportional to the speed.
The area of a rectangle is the product of its length and width.
The total cost of buying a product is the cost per unit multiplied by the number of units purchased.
The amount of work done varies directly with the number of workers.
Обяснение
Joint variation involves a variable changing proportionally with the product of two or more other variables, in a rectangle the Area = Length * Width.