In a science class, 40% of the students received a grade of A, 30% received a grade of B, and 20% received a grade of C on a project. The others fell short of a passing grade. a. If 12 students received an A, how many students were in the science class? b. How many students received a failing grade?

30, 3

Step-by-step explanation:

a. Let's call the total students x. If 40% x = 12, 0.4x = 12, x = 12/0.4 = 30 students.

b. We know that 100 - 40 - 30 - 20 = 10% of all students failed. This is 10% * 30 = 0.1 * 30 = 3 students.

pay attention in your classes and concentrate the best thing you can do to raise your test scores is to pay attention when you're supposed to be learning the material: in class!

take good notes.

do your homework.

use mnemonics and other tricks.

do practice tests.

note: the best i know.

idk

step-by-step explanation: