computer organization

please solve it with steps

III. Figure below shows a simplified timing diagram for a DRAM read operation over a bus. The access time is considered to last from t1 to t2. Then there is a recharge time, lasting from t2 to t3, during which the DRAM chips will have to recharge before the processor can access them again. Assume that the access time is 50s (micro seconds) and the recharge time is 300 us. Constructing a 64 -bit wide memory system using these chips yields what data transfer rate in Bytes/sec? [3 Marks]