size of RAM chip = 512 x 8
Memory size required = 2x 1024 bytes = (2 x 1024 x 8) bits
total number of RAM required = $\frac{2 X 1024 X 8}{512 X 8} = 4 chips$
similarly ,
size of ROM chip = 2048 x 8
Memory size required = 4 x 1024 x 8 bits
total number of ROM required = (4 x 1024 x 8) /( 2048 x 8) = 2 chips
4 RAM and 2 ROM are required