Mathematics for IGCSE & O level - Proportion (Section 3 - No. 28)
Which of the following represents a direct proportion between two variables?
y = 1/x
y = x^2
y = 5x
y = x/5
Explicaţie
Direct proportion means as one variable increases, the other also increases proportionally. In y=5x, y will increase if x increases. In y = x/5, the same behavior occurs.