Let's set up a couple of equations:
Let x = number of girls
Let y = number of boys
Graduation class = x + y
There are 535 total students, so:
535 = x + y
Since there are 149 more girls than boys:
x = y + 149
Then let us plug this equation into the equation with the total graduation class:
535 = (y + 149) + y
Then add like terms:
535 = 2y + 149
Subtract 149 to get y on one side:
386 = 2y
Divide by 2 to get the number of boys that are in the class:
y = 193
So now we know that there are 193 boys in the class.
