I assumed you meant red instead of wet.
To calculate this, multiply 28% (which is the same as .28) times 300.
300 x .28 = 84
90 - 40 = 50
Complementary angles add up to 90 degrees.
If one angle is 40 degrees less than the other, you just put it into an equation where 40 is subtracted from 90.
The answer would then be 50 degrees.
Hi there
The price before discount is
P=3÷0.15
p=20
Hope it helps