Parts a and b

To answer this question, we need to first find $1$% and then multiply by $100$ to get to the original amount.

This is given by the formula: $\frac{\text{Amount given}}{\text{Percentage}} \times 100$

In part a, $\frac{\var{a}}{\var{b}} \times 100 = \var{ans}$

Parts c, d, and e

For these parts you need to find the percentage given of the original amount first.

For part c this is $\frac{\var{a}}{{100}}\times\var{d} = \var{z}$. (Remember you can use your own method to do this, you don't necessarily have to follow this one!)

Then, you subtract (if it is a reduction) or add (if it is an increase) to the original amount: $\var{a} - \var{z} = \var{ans2}$