Question

If you received a 5% raise and your final paycheck was 100(which includes your 5% raise), how much was your original paycheck?

Answer 1

so you were earning say "x", so "x" is the 100% of  your paycheck.

but you're da bomb and so you got a raise of 5%, so the new amount of your paycheck is 100% + 5%, so is 105% really, and we happen to know that is $100.

$\bf \begin{array}{ccll} \ &\%\\ \cline{1-2} 100&105\\ x&100 \end{array}\implies \cfrac{100}{x}=\cfrac{105}{100}\implies 10000=105x \\\\\\ \cfrac{10000}{105}=x\implies 95.238\approx x$