SSC Steno Grade C and D 16 Oct 2011 Paper

Some equations are solved on the basis of a certain system. On the same basis find out the correct answer from the given alternatives for the unsolved problem.
4 × 7 × 5 × 3 = 3574, 8 × 6 × 5 × 6 = 6568, 7 × 5 × 8 × 5 = ?