What is the correct translation of the following statement into mathematical logic? "Some real numbers are rational"

Consider the virtual page reference string $$$1,2,3,2,4,1,3,2,4,1$$$
On a demand paged virtual memory system running on a computer system that has main memory size of $$3$$ page frames which are initially empty. Let $$LRU,$$ $$FIFO$$ and $$OPTIMAL$$ denote the number of page faults under the corresponding page replacement policy. Then

A file system with 300 G Byte disk uses a file descriptor with 8 direct block addresses, 1 indirect block address and 1 doubly indirect block address. The size of each disk block is 128 Bytes and the size of each disk block address is 8 Bytes. The maximum possible file size in this file system is

A process executes the code
fork $$\left( {\,\,\,} \right);$$
fork $$\left( {\,\,\,} \right);$$
fork $$\left( {\,\,\,} \right);$$
The total number of child processes created is