GCSE Maths OCR J560

Solve simple problems involving quantities in direct proportion including algebraic proportions.

e.g. Using equality of ratios, if $y ∝ x$, then

$\dfrac{y_1}{y_2} = \dfrac{x_1}{x_2}$ or $\dfrac{y_1}{x_1} = \dfrac{y_2}{x_2}$

Currency conversion problems.

see also Similar shapes, 9.04c

Solve more formal problems involving quantities in direct proportion (i.e. where $y ∝ x$).

Recognise that if $y = kx$, where $k$ is a constant, then $y$ is proportional to $x$.

Formulate equations and solve problems involving a quantity in direct proportion to a power or root of another quantity.

Solve simple word problems involving quantities in inverse proportion or simple algebraic proportions.

e.g. speed-time contexts (if speed is doubled, time is halved).

Solve more formal problems involving quantities in inverse proportion (i.e. where $y ∝ \dfrac{1}{x}$).

Recognise that if $\dfrac{k}{x}$, where $k$ is a constant, then $y$ is inversely proportional to $x$.

Formulate equations and solve problems involving a quantity in inverse proportion to a power or root of another quantity.