Question

Among the eighth-graders in Michael's school, 70% have siblings. The eighth-grade class is 5/6 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. 192

Answer 1

D. 192

Explanation:

This problem involves a few steps. First, you need to determine how many eighth graders you have given that 112 represent 70% of the total number of eighth graders. You can solve this using a proportion:

`(70)/(100)=(112)/(x)`

Cross-multiply and divide: 70x = 11200 or 70x/70 = 11200/70 or x = 160

Since there are 160 total eighth graders and this is
`(5)/(6)` of the amount of seventh graders, we can set up an equation to solve for the total amount of seventh graders:

160 =
`(5)/(6)`x

Multiply by the reciprocal of your fraction on both sides:

`(6)/(5)` x 160 =
`(5)/(6)`x (
`(6)/(5)`)

Solve for x: x = 192 seventh graders