Mrs$.$ Chavis's statistics class has $26$ students in it$,14$ girls and $12$ boys. She uses a calculator to select two students at random to solve a problem on the board. Given that the second student chosen is a girl, what is the probability that the first student was also a girl? PLease explain if this is correct or not: $(14/26+13/25/(14/26+13/25+12/26+14/25)=0\mathrm{.}518$