The discount can be found by subtracting the sale price from the original price:
$25.40 - $16.51 = $8.89
So the discount was $8.89.
To find the percent discount, we can divide the discount by the original price and multiply by 100:
$8.89 / $25.40 * 100% = 35%
Therefore, the percent discount from the coupon was 35%.