For a small box, the mass is $x\text{ kg}$. For a large box, the mass is $y\text{ kg}$.
(a)[1]
If 4 small boxes and 6 large boxes together have a mass of $30\text{ kg}$, show that $2x+3y=15$.
(b)[1]
If 6 small boxes and 1 large box have a combined mass of $13\text{ kg}$, use this to write an equation in terms of $x$ and $y$.
(c)[3]
Solve the simultaneous equations to determine the mass of a small box and the mass of a large box. Show all your working.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$4x+6y=30 \Rightarrow 2x+3y=15$ after dividing through by $2$” …