Melody

Definitely zero 

a=27     r=1/3

27+9+3+1+(1/3)+(1/9)=364/9

$$\boxed{S_n=\frac{a(1-r^n)}{1-r}}\\\\\\
\frac{364}{9}=\frac{27(1-(1/3)^n)}{1-(1/3)}}\\\\
\frac{364}{9*27}=\frac{1-(1/3)^n}{2/3}}\\\\
\frac{364*2}{9*27*3}=1-(1/3)^n\\\\
\frac{728}{729}-1=-(1/3)^n\\\\
\frac{-1}{729}=-\frac{1}{3^n}\\\\
729=3^n\\\\
log_3(729)=log_3 3^n\\\\
n=log_3(729)\\\\
n=log729/log3\\\\
n=6$$

Thank you Chris for helping me spot my previous error   

Thanks Geno, 

I had to think about that one!   

It stands for Standard Deviation.

It is a statistical term.    

OR

you can have a sD memory card.  I don't know what that stands for.    

CPhill's solution is 24 chairs and 14 tables

This gives a profit of

$${\mathtt{24}}{\mathtt{\,\times\,}}{\mathtt{450}}{\mathtt{\,\small\textbf+\,}}{\mathtt{14}}{\mathtt{\,\times\,}}{\mathtt{80}} = {\mathtt{11\,920}}$$   dollars

I will also check that this fits the limitations.

mahogony = 24*5+14*20=400 good

hours = 24*10+14*15=450  good

--------------------------------------------------------------

My solution is  45 chairs and no tables

This gives a profit of  

$${\mathtt{45}}{\mathtt{\,\times\,}}{\mathtt{450}} = {\mathtt{20\,250}}$$   dollars 

I will also check that this fits the limitations.

mahogony = 45*5=225 good

hours = 45*10=450  good

Here if my graph.   The movable line represents profit.  Basically I just added this to CPhill's graph.

Thanks Chris :)

We tried rebooting the computer but it only fixed CPhill's machine.

Mine is still malfunctioning.  I am doing my best to fix the subprocessor but it is a work in progress.  Sorry.

Neither!

This is simple interest because the money is actually PAID each day.  Each dày the money is growing so if you look at what you have at the end compared to what  you started with it will behave like compound interest.

You are not doing it wrong exacly but you are not doing it 182 times either. That's how many times simple interest has been earned.

The only sensible way to do this is with the compound interest formula.

2 x 630=1260m= 1.26km