In an undirected connected planar graph G, there are eight vertices and five faces. The number of edges in G is ______

In the context operating systems, which of the following statements is/are correct with respect to paging?

Three processes arrive at time zero with CPU bursts of 16, 20, and 10 milliseconds. If the scheduler has prior knowledge about the length of the CPU bursts, the minimum achievable average waiting for these three processes in a non-preemptive scheduler (rounded to the nearest integer) is ______ milliseconds.

Which of the following standard C library functions will always invoke a system call when executed from a single-threaded process in a UNIX/Linux operating system?