Working alone, it takes Kristen 10.2 hours to harvest a field. Kayla can harvest the same field in 16.5 hours. Find how long it would take them if they worked together.

I have been stuck on this for a while it's for pre cal I was wondering if I needed to round the decimals. This is what I have so far.
[tex] \frac{1}{10.2} + \frac{1}{16.5} = \frac{1}{x} [/tex]
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