With this type of question draw yourself a little sketch so you can see the problem.

The LEMAC (leading edge MAC) is at 625.6" aft of the datum and the CG is at 650" aft of the datum therefore the CG is 650-625.6= 24.4" in from LEMAC.

As a % of the MAC this 24.4/134.5 x 100% = 18.1%