Question 933584
Let x=number of girls
Girl to boy ratio is 9 to 8 means that for every (9+8=17) students 9/17 are girls. So
(9/17)*68=36--number of girls
Another way:
9:8=x:(68-x) or
(9/8)=x/(68-x) Cross-multiply
9(68-x)=8x
612-9x=8x
17x=612
x=36--number of girls

Did this help?--ptaylor