How do I figure out the % dilution of mixture of different strength solutions

I have three bottles of diluted tuberose absolute. One is 10 ml at a 10% dilution, the other is 5 ml at a 10% dilution, and the other is 5 ml at a 5% dilution. I already mixed them all together. How do I figure out what the resulting percentage dilution is?

10 * .1 = 1 ml of tuberose
5 * .1 = .5 ml of tuberose
5 * .05 = .25 ml of tuberose

(1 + .5 + .25) / (10 + 5 + 5) =
1.75 / 20 = 0.0875
8.75% dilution