a) calculate the acceleration of the system?

b) how long does it take the blocks to move 20 meters?

I drew a picture adn this is what i have using the formula for accel.

A = M2g-Mk*M1g/M1+M2 which gave me 5 (9.80)-.200*(8)*(9.80)/ 5+8 = 2.56 m/s^2

that was all i was able to get was i right so far and could help me on finding where i went wrong on this problem