Luis had three bags of sesame seeds, Q, R and S and the mass of each bag of sesame seeds was in the ratio 2 : 3 : 2. Luis decided to transfer 20% of sesame seeds from Bag Q into Bag R and 80% of sesame seeds from Bag S into Bag R. Given that the mass of Bag R was 20 kg in the end, how many kilograms of sesame seeds were transferred into Bag R?

	Q	R	S
Before	2 u	3 u	2 u
Change 1	- 0.4 u	+ 0.4 u
Change 2		+ 1.6 u	- 1.6 u
After	1.6 u	5 u	0.4 u

Mass of sesame seeds transferred from Bag Q into Bag R
= 20% x 2 u
= ²⁰₁₀₀ x 2 u
= 1.6 u

Mass of sesame seeds transferred from Bag S into Bag R
= 80% x 2 u
= ⁸⁰₁₀₀ x 2 u
= 1.6 u

Mass of sesame seeds in Bag R in the end
= 3 u + 0.4 u + 1.6 u
= 5 u

5 u = 20 

1 u = 20 ÷ 5 = 4

Mass of sesame seeds transferred into Bag R
= 0.4 u + 1.6 u
= 2 u
= 2 x 4
= 8 kg

Answer(s): 8 kg