Question 836211
Actually, if you spent  a total of $85.00 including meal, tax(if any) and tip, your meal (with tax if restaurant meals are taxed in the state/country where you ate) was $71.73, and you left a tip of 18.5% of $71.73, which added $13.27 for a total amount spent of
$71.73 + $13.27 = $85.00.
 
Here is how I calculate it:
{{{x}}}= amount, in $, billed for food plus tax (if any)
{{{0.185x}}}= amount, in $, left as tip
{{{x+0.185x=(1+0.185)x=1.185x}}}= total amount spent, in $.
The equation I get is {{{1.185x=85}}} and I solve it by dividing
{{{x=85/1.185}}}
I do not get an exact number.
I get $71.72996 (rounded to 5 decimal places).
It rounds to 71.73.
If 71.73 was the amount, in $, billed for food plus tax (if any),
{{{71.73*0.185=13.27005}}} would be the 18.5% tip (18.5% of 71.73).
You would round that to 13.27, and
{{{71.73+13.27=85.00}}}