A high school graduating class is made up of 511 students. There are 165 more girls than boys. How many boys are in the class?

X=number of boys.

y=number of girls.

We can suggest this system of equations:

x+y=511

y=x+165

We can solve this system by substitution method.

x + (x+165) = 511

2x=511-165

2x=346

x=346/2

x=173

y=x+165

y=173+165

y=338

Answer: there are 173 boys in the class.