What is doughnuts chart

Acomputer has a two-level cache. suppose that 60% of the memory references hit on the first level cache, 35% hit on the second level, and 5% miss. the access times are 5 nsec, 15 nsec, and 60 nsec, respectively, where the times for the level 2 cache and memory start counting at the moment it is known that they are needed (e. g., a level 2 cache access does not even start until the level 1 cache miss occurs). what is the average access time?

You wanted to look up information about alzheimer's, but you were unsure if it was spelled "alsheimer's" or "alzheimer's." which advanced search strategy would be useful? a) a boolean search b) using a wild card in your search c) trying different search engines d) doing a search for "alsheimer's not alzheimer's" asap. ill give brainlist.

Need ! will choose brainliest! discuss the role of abstraction in the history of computer software.