Answer: percentage of profit on the skirt is 11.1%
Step by step:
Let G denote price of gloves, and S the price of skirt, and let g dente the original cost of the gloves and s the cost of skirt. I will be using $ for the currency unit instead of the pound.
The sale equation is
$48 = G + S
100% profit on the gloves means:
G = 2 * g = 2 * $4
On the skirt, the profit is unknown ("x"):
S = x + s
We know that the total profit (total sale - total cost) after the sale is is 20%:
$48 - (s + $4) = 0.2 * (s + $4)
which finally gives us two equations with two unknowns:
$48 - (s + $4) = 0.2 * (s + $4)
$48 = 2 * $4 + x + s
which is straight-forward to solve. I got solutions as follows:
s = $36, x = $4
so the percentage of profit on the skirt is 100% * 4/36 = 11.1%