Answer:
$30
Explanation:
They didn't write the question very clearly, but I would imagine it means the sale was 25% off.
If so, that means Sandra bought the quilt at 75% of the original price. This is because 100% (full price) - 25% = 75%.
75% x 40 = 0.75 x 40 = 30
Sandra pays $30 for the quilt.