Wendy had four boxes, V, W, X and Y which contained a total of 270 kiwis. She transferred 13 kiwis from Box V to Box W, 39 kiwis from Box W to Box X and 91 kiwis from Box X to Box Y. The ratio of the number of kiwis in Box V to Box W to Box X changed from  2 : 7 : 11 to 1 : 5 : 7. How many kiwis were in Box Y at first?

	Make p the same (1)x5 = (3)	V (1)	W (2)	X	Y
Before	10 u	2 u	7 u	11 u	?
Change 1	- 65	- 13	+ 13
Change 2			- 39	+ 39
Change 3				- 91	+ 91
After	5 p	1 p	5 p	7 p	?

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

7 u + 13 - 39 = 5 p
7 u - 26 = 5 p --- (2)

(1) _{x 5}
10 u - 65 = 5 p --- (3)

Make p the same.

(3) = (2)
10 u - 65 = 7 u - 26
10 u - 7 u = 65 - 26
3 u = 39

1 u = 39 ÷ 3 = 13

Total number of kiwis in Box V, Box W and Box X
= 2 u + 7 u + 11 u
= 20 u

Total number of kiwis in Box Y at first
= 270 - 20 u
= 270 - 20 x 13
= 270 - 260
= 10

Answer(s): 10