Hi Guys,
Thanks for all the replies.
So, the solution that brings me closest to the provided answer is to multiply the LDR by 1.67. I guess since it is it Alternate airport, the wet factor doesnt apply for planning purposes.
6,200 * 1.67 = 10,354
Provided answer: 10,333
So pretty close. I will stick with that rule for the test.
Thanks again guys until next time

Really appreciate all your replies.