5) (15 pts) As shown in the following figure, there is an institutional network connected to the Internet. Suppose that the average object size is 500,000 bits and that the average request rate from the institution's browsers to the original servers is 20 requests per see- ond. Also suppose that the amount of time it takes from when the router on the Internet side of the access link forwards an HTTP request until it receives the response is 5 sec- onds on average. Note that the total average response time is the sum of the average ac- cess delay (i.e., the delay between the two routers shown in the picture) and the average Internet delay (ie.. 5 seconds on average). For the average access delay, use / (1- BA), where is the average time to send an object over access link, is the arrival rate of objects to access link, and is called the traffic intensity. a) (8pts) Find the total average response time. origin servers public Internet seconds 15 Mbps access linik 100 Mbps LAN b) (7pts) Now suppose a cache is installed in the institutional LAN. Suppose the hit rate is 0.6. Find the total response time