25% of the people are performers for a concert and the rest are spectators. 80% of the spectators are children and there are 900 less adult spectators than child spectators. How many child spectators must join so that 84% of the people are child spectators?
|
Performers |
Spectators |
|
1x5 |
3x5 |
|
|
Adults |
Children |
|
|
1x3 |
4x3 |
Before |
5 u |
3 u |
12 u |
Change |
|
|
+ ? |
After |
4x2 = 8 u |
21x2 = 42 u |
25% =
25100 =
14 80% =
80100 =
45 84% =
84100 =
2125The total number of spectators at first is repeated. Make the total number of spectators the same. LCM of 3 and 5 is 15.
Number of less adult spectators than child spectators at first
= 12 u - 3 u
= 9 u
9 u = 900
1 u = 900 ÷ 9 = 100
If some child spectators join, the total number of adult spectators and performers remains unchanged.
Number of child spectators who must join so that 84% of the people are child spectators
= 42 u - 12 u
= 30 u
= 30 x 100
= 3000
Answer(s): 3000