20% of the people are performers for a concert and the rest are spectators. 80% of the spectators are children and there are 240 more child spectators than parent spectators. How many child spectators must leave so that 55% of the people are child spectators?
|
Performers |
Spectators |
|
1x5 |
4x5 |
|
|
Parents |
Children |
|
|
1x4 |
4x4 |
Before |
5 u |
4 u |
16 u |
Change |
|
|
- ? |
After |
9x1 = 9 u |
11x1 = 11 u |
20% =
20100 =
15 80% =
80100 =
45 55% =
55100 =
1120The total number of spectators at first is repeated. Make the total number of spectators the same. LCM of 4 and 5 is 20.
Number of more child spectators than parent spectators at first
= 16 u - 4 u
= 12 u
12 u = 240
1 u = 240 ÷ 12 = 20
If some child spectators leave, the total number of parent spectators and performers remains unchanged.
Number of child spectators who must leave so that 55% of the people are child spectators
= 16 u - 11 u
= 5 u
= 5 x 20
= 100
Answer(s): 100