Mathematics for IGCSE & O level - Proportion (Section 1 - No. 13)

Which scenario describes direct proportion?

The time taken to complete a journey and the speed of travel.

The number of workers and the time it takes to build a house.

The number of products sold and the total revenue earned.

The price of an item and the quantity of that item you can buy with a fixed amount of money.

Direct proportion means both variables increase or decrease proportionally. Revenue increases as sales increase.