It cost $420 to print flyers encouraging people to vote yes for the rights of indigenous people. The printing company prints the order for 10% off, how much will you pay
+33661 10% off means they will pay 90% of the basic cost. 90% of 420 is
$${\frac{{\mathtt{90}}}{{\mathtt{100}}}}{\mathtt{\,\times\,}}{\mathtt{420}} = {\mathtt{378}}$$ so they pay $378
Alternatively, you can take 10% of $420 (that is, one-tenth of $420), namely $42, and subtract this from $420.
$420 - $42 = £378
+33661 10% off means they will pay 90% of the basic cost. 90% of 420 is
$${\frac{{\mathtt{90}}}{{\mathtt{100}}}}{\mathtt{\,\times\,}}{\mathtt{420}} = {\mathtt{378}}$$ so they pay $378
Alternatively, you can take 10% of $420 (that is, one-tenth of $420), namely $42, and subtract this from $420.
$420 - $42 = £378
