To find this cache you need to visit the cache Alphabet W - What a Wonderful World of Words (GCNP8X) first. There you will find the values of A and B.
The given coordinates have nothing to do with the cache. You have to determine and visit four locations called legs, and collect their coordinates and the information stated below. All legs are located within the city limits of Helsinki, but they are quite far from each other. With the coordinates of the legs, you will be able to either calculate or graphically solve a reference point. From the other information collected at the previous cache (the values of A and B) and at the legs of this cache (the values of C, D, E, and F), you will obtain an offset to calculate the final coordinates from the coordinates of the reference point. The four legs are independent of each other, so you can visit them in any order.
LEG 1: There is an “eternal flame” somewhere by the seashore. Within a radius of 200 meters around the flame, look for a letter X (actually more like a plus sign). Record the coordinates of the alphabet X. There is also a spherical object upon the X. Let the number of letters in the name of the color (paint) of the spherical object be C.
LEG 2: There is a park whose name suggests that there is something very valuable in it. The name of a street leading to the park implies that something is hidden, and the names of the streets on the north and west side make one think that someone is searching for what is hidden there. By the street passing (not a dead end) the park on the south side, there is another alphabet X on the sidewalk. Record the coordinates of the X. Find an elliptical metal plaque on the nearest lamppost. Let the higher value of the two numbers on the plaque be D. Hint added 29 Dec 2007: The X is totally worn out. It used to be by the lamppost with a tag (graffiti) like "8" over "Z." Hint added 24 Jan 2014: The lamppost is east of the park. A similar graffiti can be found by the park, but it is the wrong one.
LEG 3: Find 90M1012, which is situated on an island. There is a third alphabet X there. Record the coordinates of the X. When you stand there facing approximately to the north, you will see an information sign. Let the number of letters in the first word of the sign be E.
LEG 4: There is a park whose name suggests that something is hidden in it or that the park itself is hidden. When you enter the park along the only public walkway, you will see a prohibition sign that forbids some kind of action, which everyone already should know to be forbidden. There is no alphabet X here, but record the coordinates of the prohibition sign. Let the number of letters in the first word of the sign be F.
REFERENCE POINT: Mark the four legs on the map, and draw two lines that connect the legs. Now, you have a really big alphabet X, which covers a substantial part of the city. The four legs are the end points of the big alphabet X, and the reference point is the center of the X where the lines cross. If you like to determine the exact reference point, you should calculate it from the coordinates (the legs then being arcs of great circles), but a graphical solution will be enough if you measure and draw carefully.
FINAL COORDINATES: Calculate the final coordinates by adding an offset of 10 (A + C + D + E + F) – 373 thousandths of a minute to the latitude of the reference point and 10 (100 B + C + D + E + F) – 817 thousandths of a minute to the longitude of the reference point.