McGraw Hill Glencoe Algebra 2, 2012
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McGraw Hill Glencoe Algebra 2, 2012 View details
8. Solving Systems of Equations Using Inverse Matrices
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Exercise 46 Page 204

Check the number of students first.

C

Practice makes perfect

Since this is a multiple choice question, we can find the correct answer by eliminating the options that are certainly not correct.

Checking the Number of Students

It is given that 225 students voted for the theme A Night Under the Stars and 480 students voted for the theme The Time of My Life. The sum of these two numbers gives the total number of students who voted. Total number of votes:225+480=705Let's check the total number of votes in the options and highlight the ones where the total of boy and girl votes is 705.

Option Boys Girls Total
A 176 351 527
B 395 310 705
C 380 325 705
D 705 325 1030
E 854 176 1030

We can see that options A, D, and E can be eliminated.

Checking the Vote Distribution

Let's concentrate now on how many boys and girl voted for the theme A Night Under the Stars.

  • It is given that 40 % of the girls voted for this theme.
  • It is also given that 75 % of the boys did not vote for this theme, so 100 %-75 %=25 % of the boys voted for this theme.

Let's see the numbers corresponding to these percentages in options B and C that are not eliminated so far.

Votes for The Night Under the Stars
Option 25 % of Boys 40 % of Girls Total
B 0.25*395=98.75 0.40*310=124 222.75
C 0.25*380=95 0.40*325=130 225

We can see that the number in option C matches the number of votes given in the question, so option C is the correct answer.