I think 100% profit means she got the gloves for free so all her revenue was profit. That can't be right. Let's assume 'profit on the cost' means a 100% markup, meaning she sold the gloves for £8.
That means she sold the skirt for £40.
She made 20% profit on the total cost t so
1.2 t = 48
t = 48/1.2 = 40
Since she spent £4 on the gloves that means she spent £36 on the skirt she sold for £40.
So she made £4 on a cost of £36 for a percentage of 1/9=.11111...
Answer: 11.1%