Discount

$$\left({\mathtt{1}}{\mathtt{\,-\,}}{\mathtt{0.15}}\right){\mathtt{\,\times\,}}{\mathtt{210}} = {\frac{{\mathtt{357}}}{{\mathtt{2}}}} = {\mathtt{178.5}}$$

$178.5

If it's on sale with a 15% discount off the original price, then the sale price must just be 85% of the original price.

So 85% x 210 = $178.50

Thanks CPhill