Was it 700 as per II Samuel 10:18 “And the Syrians fled before Israel; and David slew the men of seven hundred chariots of the Syrians, and forty thousand horsemen, and smote Shobach the captain of their host, who died there.” (KJV)
Or was it 7,000 as per I Chronicles 19:18 “But the Syrians fled before Israel; and David slew of the Syrians seven thousand men which fought in chariots, and forty thousand footmen, and killed Shophach the captain of the host.” (KJV)
Again, there are no contradictions in the Bible. In II Samuel 10:18, the Bible tells us the number of men King David slew of 700 chariots. If Solomon had 10 men per chariot, then the number of men David slew was 7,000 which is confirmed in 1 Chronicles 19:18. So clearly, the Syrians had 10 horsemen per chariot.
As you can see, this is NOT a contradiction.