Three types of bread flour, V, W and X come in containers of 90 g, 180 g and 210 g respectively. Containers of V, W and X are mixed together in the ratio 1 : 3 : 4 to obtain 13.23 kg of an assortment of bread flour.

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

	V	W	X
Number	1 u	3 u	4 u
Value	90	180	210
Total value	90 u	540 u	840 u

(a)
Total mass of bread flour
= 90 u + 540 u + 840 u
= 1470 u

1470 u = 13230

1 u = 13230 ÷ 1470 = 9

Total number of containers of V and W used
= 1 u + 3 u
= 4 u
= 4 x 9
= 36 

(b)
Combined weight of all the bread flour in containers W and containers X
= 540 u + 840 u
= 1380 u

Difference between the combined weight of all the bread flour in containers W and containers X as compared to the bread flour in containers V
= 1380 u - 90 u
= 1290 u
= 1290 x 9
= 11610 g
= 11.61 kg 

Answer(s): (a) 36; (b) 11.61 kg