A5. A number line starts at -55 and ends at 55 . If we start at -55 , what percentage of the way along is the number 5.5?
Solution
$\mathbf{5 5 \%}$

The distance from -55 to 55 is 110 . The distance from -55 to 0 is 55 and from 0 to 5.5 it is 5.5. Therefore the distance from -55 to 5.5 is $55+5.5$.

As a percentage of the total distance this is $\frac{55+5.5}{110} \times 100=\frac{55+5.5}{11} \times 10=(5+0.5) \times 10$ $=50+5=55$.