There are 18 boys in a class there are w fewer boys than girls how many students are there in the class

The Number of boys in the class is: 18

 Let's call "g" to the number of girls in the class.

 The problem says that there is "w" fewer boys than girls, so we have:

 g-w=18

 Then, the number of girls in the class  is:

 g=18+w

 Let's call "x" to the total number of studens in the class:

 x=g+18

 When we substitute g=18+w  into x=g+18, we obtain:

 x= (18+w)+18

 The total number of studens in the class is:

 x=w+36