Warren had three bags of potato starch, R, S and T and the mass of each bag of potato starch was in the ratio 3 : 3 : 5. Warren decided to transfer 10% of potato starch from Bag R into Bag S and 80% of potato starch from Bag T into Bag S. Given that the mass of Bag S was 36.5 kg in the end, how many kilograms of potato starch were transferred into Bag S?

	R	S	T
Before	3 u	3 u	5 u
Change 1	- 0.3 u	+ 0.3 u
Change 2		+ 4 u	- 4 u
After	2.7 u	7.3 u	1 u

Mass of potato starch transferred from Bag R into Bag S
= 10% x 3 u
= ¹⁰₁₀₀ x 3 u
= 2.7 u

Mass of potato starch transferred from Bag T into Bag S
= 80% x 5 u
= ⁸⁰₁₀₀ x 5 u
= 4 u

Mass of potato starch in Bag S in the end
= 3 u + 0.3 u + 4 u
= 7.3 u

7.3 u = 36.5 

1 u = 36.5 ÷ 7.3 = 5

Mass of potato starch transferred into Bag S
= 0.3 u + 4 u
= 4.3 u
= 4.3 x 5
= 21.5 kg

Answer(s): 21.5 kg