The ratio of boys to girls in a class room is 7 to 11. if there are a total of 49 girls in the classroom, then how many boys and girls are there all together?

Setup Ratio-

7 boys : 11 girls

x boys : 49 girls

 

Cross Multiply-

7*49 = 11x

 

Simplify-

343 = 11x

 

Divide-

343/11 = 31.18

 

Answer-

About 31 boys

EDIT:

7 out of 18 in the class are boys...

so 11 out of 18 are girls

 

11 is to 18   as  49 is to 'x'      where 'x' is the total number of boys and girls

 

11/18 = 49/x

x = 49 x 18/11 = ~80 total

 

49 girls    ~~ 31 boys