Question 1124792
one way to do this is make the selling price $100
one gown cost x, and .25x was the gain.  Therefore, 1.25 x was the selling price, $100, and the gown cost $80 (gain of $20 was 25%)
one gown cost y, and .25y was the loss.  Therefore, 0.75 y was the selling price, $100, and the gown cost $133.33.

The gowns together cost $213.33 and sold for $200.  This is a 6.25% loss.
D