Thanks and I heard this one a few years ago from an airline guy and forgot about it. Finding the 30 deg. x-wind is easy because it's half. The 0, 60, and 90 ones are obvious so don't waste time calculating those. That leaves you needing the 45 deg. item which is a little tricky, how do you find 0.7 of something. What you can do with that one is think in units of ten and add 7 knots for each 10 knots of wind. Ex. 35 knots at 45 degrees, that's 3 wind units x 7 knots = 21 plus some change, say half the original value, so 24.5 which is very close to the correct answer (24.7). I would be happy if I quit thinking about it when I got the 21 personally.