Chlorineviz
Answered

A certain class consists of 45 grade 8 students. The no. of boys is 9 more than the no. of girls. How many boys and girls are there? (Solving systems of linear equations using elimination method)

Sagot :

sol. let x  be the number of girls
            y be the number of boys

           x + y = 45
           y = x + 9
        x + x + 9 = 45
         2x = 45 - 9
         2x = 36     or x = 18
   Therefore : girls = 18
                     boys = 27
      
Let x = no. of girls
x + 9 = no. of boys

x + x + 9 = 45
    2x + 9 = 45
2x + 9 -9 = 45 - 9
         2x  = 36
    2x ÷ 2 = 36 ÷ 2
            x = 18 - no. of girls
      x + 9 = 27 - no. of boys