There are 81 girls to every 72 boys in total, which can be represented by 81/72, which put into decimal form, is 1.125. If you then take the number of boys in the group, 16, and multiply it by this number (because the problem states that the ratio is constant) you can find the number of girls in the group.
16*1.125=18
So there are 18 girls in a group with 16 boys.
If this is a system of equations then:
Multiply 5x-y=3 by -2
=> -10x+2y=-6
Now you sum the equations:
10x-10x+7y+2y=-3-6
=> 9y=-9
Then just divide by 9: y=-1
Now to get x, choose one of the equations and use the value we got from y:
5x-(-1)=3 => 5x+1=3 => 5x=3-1
=> 5x=2
=> x=2/5
(x,y)=(2/5, -1)
Answer:
0.975
Step-by-step explanation:
It is c. If you do the equation it is -1 1/4
