10% of the people are performers for a concert and the rest are spectators. 60% of the spectators are adults and there are 1260 less child spectators than adult spectators. How many adult spectators must join so that 77% of the people are adult spectators?
|
Performers |
Spectators |
|
1x5 |
9x5 |
|
|
Children |
Adults |
|
|
2x9 |
3x9 |
Before |
5 u |
18 u |
27 u |
Change |
|
|
+ ? |
After |
23x1 = 23 u |
77x1 = 77 u |
10% =
10100 =
110 60% =
60100 =
35 77% =
77100 =
77100The total number of spectators at first is repeated. Make the total number of spectators the same. LCM of 9 and 5 is 45.
Number of less child spectators than adult spectators at first
= 27 u - 18 u
= 9 u
9 u = 1260
1 u = 1260 ÷ 9 = 140
If some adult spectators join, the total number of child spectators and performers remains unchanged.
Number of adult spectators who must join so that 77% of the people are adult spectators
= 77 u - 27 u
= 50 u
= 50 x 140
= 7000
Answer(s): 7000