Answer:
The number of boys in the class is 9
Step-by-step explanation:
The question in English is
There are 27 students in one class. If 3 girls and 4 boys leave the class, the number of girls will be three times the number of boys. How many boys are in the class?
Let
x -----> the number of boys
y -----> the number of girls
we know that
[tex]x+y=27[/tex] -----> [tex]y=27-x[/tex] -------> equation A
[tex]y-3=3(x-4)[/tex] ----> equation B
substitute equation A in equation B and solve for x
[tex](27-x)-3=3(x-4)[/tex]
[tex]24-x=3x-12[/tex]
[tex]3x+x=24+12[/tex]
[tex]4x=36[/tex]
[tex]x=9\ boys[/tex]
therefore
The number of boys in the class is 9
