The chart above shows the distribution of letter grades for three groups of students on one test. Point values are assigned to the letter grades so that A = 4 points, B = 3 points, C = 2 points and D = 1 point. Which of the following values is the closest to the average (arithmetic mean) grade of students in the group 3?

A. 2.2
B. 2.4
C. 2.9
D. 3.1
E. 3.6

(B) There are 4 + 7 + 9 + 2 = 22 students in the group 3.

The grade distribution in the group 3 was:
4 students received D;
7 students received C;
9 students received B;
2 students received A.

Therefore, the sum of the grade points for the group 3 is:
(4 × 1) + (7 × 2) + (9 × 3) + (2 × 4) = 4 + 14 + 27 + 8 = 53.

We can find the average grade in gr the group 3 by dividing this sum by the number of students in the group 3:
Average for the group 3 = 53/22.
Performing the required division, we see that 2.4 is the closest answer choice.

The correct answer is choice (B).
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I did not understand the question, could you please elaborate. Which groups are we talking about?

We have three groups of students given by the chart:


Each group is presented by its color. For example, all the green bars represent the group #2:


The first (from left) green bar tells us that 5 students in the group #2 have received a "D" mark on the test:


The rest of the bars can be interpreted similarly.

Please, specify which part exactly is not clear to you.