So,
The secret to solving problems with ratios is to find the value of one unit.
5:7 = 12 units total
To find one unit, divide the total number of students by the total number of units.
600/12 = a
Simplify
50/1 = a
50 = a
The value of each unit is 50.
Now, multiply the units by the numbers in the ratio.
50(5) = b
250 = boys
50(7) = x
350 = x
There are 350 girls.
You have the value for y, so you substitute that equation for y, times three because there are three yS.
So you have: 2x + 3y = 10
2x + 3 x 2x + 4 or 2x + 3(3x + 4)
so the answer would be B, 2x + 3(3x + 4)
Answer with explanation show in Image...
I hope you understand...
