Three types of bread flour, B, C and D come in containers of 240 g, 360 g and 480 g respectively. Containers of B, C and D are mixed together in the ratio 1 : 2 : 4 to obtain 34.56 kg of an assortment of bread flour.

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

	B	C	D
Number	1 u	2 u	4 u
Value	240	360	480
Total value	240 u	720 u	1920 u

(a)
Total mass of bread flour
= 240 u + 720 u + 1920 u
= 2880 u

2880 u = 34560

1 u = 34560 ÷ 2880 = 12

Total number of containers of B and C used
= 1 u + 2 u
= 3 u
= 3 x 12
= 36 

(b)
Combined weight of all the bread flour in containers C and containers D
= 720 u + 1920 u
= 2640 u

Difference between the combined weight of all the bread flour in containers C and containers D as compared to the bread flour in containers B
= 2640 u - 240 u
= 2400 u
= 2400 x 12
= 28800 g
= 28.8 kg 

Answer(s): (a) 36; (b) 28.8 kg