Suppose that a 2M x 16 main memory is built using 256kB x 8 RAM chips and memory is word addressable, how many RAM chips are necessary?

16 RAM chips

Explanation:

To calculate the number of RAM chips needed, we divide the total size of the main memory by the size of each RAM chip. Hence:

Number of RAM chips required = Main memory size / size of one RAM

2M = 2²¹, 16 = 2⁴, 256K = 2¹⁸, 8 = 2³

Hence:

Number of RAM chips required = (2²¹ * 2⁴) / (2¹⁸ * 2³) = 2⁴ = 16

Therefore 16 RAM chips are necessary