help with percentages

[db]

Not sure if here's the best place for this but I thought I'd try.

I have been trying to figure out something and I have 2 figures (I hope one of them is correct!) can anyone tell me which one please.

I have 5.17kg something. This 5.17kg is A + 20%
If I want to increase A by 40%, what will the new total be?

I don't want to confuse the issue by adding my figures, but will do so if needed.
Thanks

[db]

Many thanks for that, I had 6.02 but rounding will have made the difference.
People with letters after their name convinced me otherwise and I've turned my brain to mush trying to follow them.

[db]

Today's letters were it's25%not20%