For the base case in this section, as a percentage of sales, COGS $-70$ percent, SGA $-14$ percent, R$\backslash$&D $-2\mathrm{.}8$ percent. Depreciation, Interest expense are fixed as stated. Tax Rate is $21$ percent.

$1.$a

Given the following case, calculate the independent effects of a $1$ percent increase in Gross Margin, a $1$ percent decrease in the TaxRate, and a $5$ percent increase in Sales.