10% of the people are performers for a concert and the rest are spectators. 60% of the spectators are parents and there are 540 more parent spectators than child spectators. How many parent spectators must leave so that 8% of the people are parent spectators?

	Performers	Spectators
	1x5	9x5
		Children	Parents
		2x9	3x9
Before	5 u	18 u	27 u
Change			- ?
After	23x1 = 23 u		2x1 =  2 u

10% = ¹⁰₁₀₀ = ¹₁₀ 

60% = ⁶⁰₁₀₀ = ³₅ 

8% = ⁸₁₀₀ = ²₂₅

The 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 more parent spectators than child spectators at first
= 27 u - 18 u
= 9 u

9 u = 540

1 u = 540 ÷ 9 = 60

If some parent spectators leave, the total number of child spectators and performers remains unchanged.  

Number of parent spectators who must leave so that 8% of the people are parent spectators
= 27 u - 2 u
= 25 u
= 25 x 60
= 1500

Answer(s): 1500