Three types of rice flour, K, L and M come in containers of 160 g, 240 g and 280 g respectively. Containers of K, L and M are mixed together in the ratio 2 : 3 : 4 to obtain 12.96 kg of an assortment of rice flour.

1. How many containers of K and L are used altogether?
2. Find the difference between the combined weight of all the rice flour in containers L and containers M as compared to the rice flour in containers K. Express the weight in kilograms.

	K	L	M
Number	2 u	3 u	4 u
Value	160	240	280
Total value	320 u	720 u	1120 u

(a)
Total mass of rice flour
= 320 u + 720 u + 1120 u
= 2160 u

2160 u = 12960

1 u = 12960 ÷ 2160 = 6

Total number of containers of K and L used
= 2 u + 3 u
= 5 u
= 5 x 6
= 30 

(b)
Combined weight of all the rice flour in containers L and containers M
= 720 u + 1120 u
= 1840 u

Difference between the combined weight of all the rice flour in containers L and containers M as compared to the rice flour in containers K
= 1840 u - 320 u
= 1520 u
= 1520 x 6
= 9120 g
= 9.12 kg 

Answer(s): (a) 30; (b) 9.12 kg