4/7 of the students in a classroom are girls if there are nine boys in the class how many total students are there ?
a.14
b.28
c.21
d.12

21 students were in the class.

Step-by-step explanation:

The information in the question tells you that 4/7 of the class is girls.

That means that the remainder of the class is 1 - 4/7 = 3/7 boys

Let the total in the class = x

(3/7)x = 9           Multiply by 7

(3/7)*7*x = 9 * 7 Simplify the right and left

3x = 63              Divide by 3

3x/3 = 63/3

x = 21

There were 21 students in the class.

graph b

step-by-step explanation:

one solution- graph a (clear intercepting point.)

no solution- graph b (they're parallel, there will never be a point of interception.)

infinite solutions- graph c (all points intercept.)