solving this algebraically , If t ties cost d dollars, how many dollars would t+1 ties cost ??
note:show your answer...
$\displaystyle t$ ties cost $\displaystyle d$ dollars
1 tie costs $\displaystyle \frac{d}{t}$ dollars
adding the cost for t ties and 1 tie ...
$\displaystyle d + \frac{d}{t}$ which does not equal $\displaystyle \frac{d+t}{t}$
note ...
$\displaystyle d + \frac{d}{t} = \frac{dt}{t} + \frac{d}{t} = \frac{dt+d}{t} = \frac{d(t+1)}{t} = \frac{d}{t}(t+1)$
... which is the cost of one tie times (t+1) ties