Three types of bread flour, K, L and M come in containers of 180 g, 300 g and 360 g respectively. Containers of K, L and M are mixed together in the ratio 2 : 3 : 4 to obtain 21.6 kg of an assortment of bread flour.

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

	K	L	M
Number	2 u	3 u	4 u
Value	180	300	360
Total value	360 u	900 u	1440 u

(a)
Total mass of bread flour
= 360 u + 900 u + 1440 u
= 2700 u

2700 u = 21600

1 u = 21600 ÷ 2700 = 8

Total number of containers of K and L used
= 2 u + 3 u
= 5 u
= 5 x 8
= 40 

(b)
Combined weight of all the bread flour in containers L and containers M
= 900 u + 1440 u
= 2340 u

Difference between the combined weight of all the bread flour in containers L and containers M as compared to the bread flour in containers K
= 2340 u - 360 u
= 1980 u
= 1980 x 8
= 15840 g
= 15.84 kg 

Answer(s): (a) 40; (b) 15.84 kg