Answer:
8 boys.
Explanation:
Lets say b is the number of boys and g is the number of girls.
We know that:
23 = b + g
g = b + 7
So then lets solve for b:
23 = b + g
23 = b + ( b + 7)
Simplify.
23 = 2b + 7
Subtract 7 from both sides to isolate the b.
16 = 2b
Divide both sides by 2.
8 = b
So there are 8 boys in the class.
We can check our work by substituting the value of b into our equation.
23 = b + ( b + 7)
23 = 8 + ( 8 + 7 )
23 = 8 + 15
23 = 23
So therefore our answer is correct.