At the tourist attraction were some adults. ¹₂ of the number of tourists was equal to 2 times the number of locals. When another 18 locals entered and 33 tourists left, the ratio of the number of tourists to the number of locals become 7 : 3. Find the number of tourists at the tourist attraction at first.

	Make p the same (1)x3 = (3)	Tourists (1)	Locals (2)	Make p the same (2)x7 = (4)
Before	12 u	4 u	1 u	7 u
Change	- 99	- 33	+ 18	+ 126
After	21 p	7 p	3 p	21 p

12 of the tourists = 2 times of the locals 
1x22x2 of the tourists = 2x11x1 of the locals 

Make the numerators the same.  LCM of 1 and 2 is 2.
²₄ of the tourists = ²₁ of the locals 

Tourists : Locals = 4 : 1

Make p the same.

(3) = (4)
12 u - 99 = 7 u + 126
12 u - 7 u = 126 + 99
5 u = 225

1 u = 225 ÷ 5 = 45

Number of tourists at the tourist attraction at first
= 4 u
= 4 x 45
= 180

Answer(s): 180