Answer: y = 3x/4
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Work Shown:
x = number of 7th grade students
y = number of 8th grade students
x/y = 4/3
3x = 4y
4y = 3x
y = 3x/4
If we knew the value of x, then we can also figure out the value of y, or vice versa. That expression in bold is equivalent to writing y = (3/4)x and it's also equivalent to y = 0.75x since 3/4 = 0.75; feel free to pick whichever format you prefer.