Question

Students in a dance class filled out a survey. There were 25 girls and some boys who

participated in the survey. The results showed that 20% of the students prefer tap dance to
ballroom dance. There are 9 students who prefer tap dance. Which equation can be used to
find the number of boys ( x) who participated in the survey?
A. 0.2 x + 25 = 9
B. 0.2( x + 25) = 9
C. 0.2(25 – 9) = x
D. 25 + x = 0.2 × 9

Answer 1

B . Because it explains their was 25 girls and some boys so you add x to the 25
(X+25)0.2= 9

Answer 2

Given:
Girls = 25
Boys = ?
Number of students who prefer tap dance = 9
percentage of students who prefer tap dance = 20%

We need to divide 9 by 20% to get the total number of students who filled out a survey.

9 ÷ 20% = 45 total number of students

Girls + Boys = 45
25 + Boys = 45
boys = 45 - 25
boys = 20

The correct equation is: B. 0.2(x + 25) = 9

0.2x + 5 = 9
0.2x = 9 - 5
0.2x = 4
x = 4 / 0.2
x = 20