Joelle had four containers, W, X, Y and Z which contained a total of 265 starfruits. She transferred 13 starfruits from Container W to Container X, 36 starfruits from Container X to Container Y and 33 starfruits from Container Y to Container Z. The ratio of the number of starfruits in Container W to Container X to Container Y changed from  3 : 7 : 12 to 1 : 3 : 9. How many starfruits were in Container Z at first?

	Make p the same (1)x3 = (3)	W (1)	X (2)	Y	Z
Before	9 u	3 u	7 u	12 u	?
Change 1	- 39	- 13	+ 13
Change 2			- 36	+ 36
Change 3				- 33	+ 33
After	3 p	1 p	3 p	9 p	?

3 u - 13 = 1 p --- (1)

7 u + 13 - 36 = 3 p
7 u - 23 = 3 p --- (2)

(1) _{x 3}
9 u - 39 = 3 p --- (3)

Make p the same.

(3) = (2)
9 u - 39 = 7 u - 23
9 u - 7 u = 39 - 23
2 u = 16

1 u = 16 ÷ 2 = 8

Total number of starfruits in Container W, Container X and Container Y
= 3 u + 7 u + 12 u
= 22 u

Total number of starfruits in Container Z at first
= 265 - 22 u
= 265 - 22 x 8
= 265 - 176
= 89

Answer(s): 89