The 50% of 80 will be the halve, the 25% will be the halve of the 50%, the 10% 80/10 the 5% will be halve of it, 1 percent will be 80/100 and so on to the table will be:
[tex]\begin{gathered} 50\to40 \\ 25\to20 \\ 10\to8 \\ 5\to4 \\ 1\to0.8 \\ 0.5\to0.4 \\ 0.1\to0.08 \end{gathered}[/tex]So to fund the 15.7% we can add the 10% plus the 5% plus the 0.5% plus 2 times the 1% so:
[tex]8+4+0.4+2(0.08)=12.56[/tex]
