Question

Write the equations for the following relations and find the unknown values: [3 MARKS]

a) One-third of a number plus 5 is 8.

b) A number is multiplied by 4 and the product is added to 8 to get double the original number.

c) The difference between three times $x$ and 11 is 31.

Answer 1

Each part: 1 Mark

The equations are as follows:

a) Let the number be $x$
$\frac{x}{3}+5=8$.
$\frac{x}{3}=8-5$.
$\frac{x}{3}=3$.
$x=9$.

b) Let the number be $x$
$(4\times x)+8=2\times x$.
$4x+8=2x$.
$4x-2x=-8$.
$2x=-8$.
$x=-4$

c) $(3\times x)-11=31$.
$3x-11=31$.
$3x=31+11$.
$3x=42$.
$x=14$.