(a)[2]
In terms of $x$, write an expression for the total number of pens in the box. Give your answer in its simplest form.
(b)[2]
The box contains $27$ pens altogether. Find how many of them are red.
Mathematics 4024 · O Level · Equations
Equations — practice question
A box contains red pens, blue pens and black pens. There are $x$ red pens. The number of blue pens is $5$ greater than the number of red pens. The number of black pens is $2$ times the number of blue pens.