Anna had four boxes, Q, R, S and T which contained a total of 328 starfruits. She transferred 50 starfruits from Box Q to Box R, 110 starfruits from Box R to Box S and 232 starfruits from Box S to Box T. The ratio of the number of starfruits in Box Q to Box R to Box S changed from  3 : 5 : 9 to 1 : 5 : 7. How many starfruits were in Box T at first?

	Make p the same (1)x5 = (3)	Q (1)	R (2)	S	T
Before	15 u	3 u	5 u	9 u	?
Change 1	- 250	- 50	+ 50
Change 2			- 110	+ 110
Change 3				- 232	+ 232
After	5 p	1 p	5 p	7 p	?

3 u - 50 = 1 p --- (1)

5 u + 50 - 110 = 5 p
5 u - 60 = 5 p --- (2)

(1) _{x 5}
15 u - 250 = 5 p --- (3)

Make p the same.

(3) = (2)
15 u - 250 = 5 u - 60
15 u - 5 u = 250 - 60
10 u = 190

1 u = 190 ÷ 10 = 19

Total number of starfruits in Box Q, Box R and Box S
= 3 u + 5 u + 9 u
= 17 u

Total number of starfruits in Box T at first
= 328 - 17 u
= 328 - 17 x 19
= 328 - 323
= 5

Answer(s): 5