Among the eighth-graders in michael’s school, 70% have siblings. the eighth-grade class is the size of the seventh-grade class.
if 112 eighth-graders have siblings, how many students are in the seventh grade?

a. 128

b. 134

c. 160

d. 920

i need quick

your answer would be C

Step-by-step explanation:

do the proportional relationship equation.

112 is 70% of what number?

you would get 160

112*100divided by 70

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: