Three types of bread flour, X, Y and Z come in containers of 120 g, 150 g and 210 g respectively. Containers of X, Y and Z are mixed together in the ratio 1 : 2 : 4 to obtain 8.82 kg of an assortment of bread flour.

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

	X	Y	Z
Number	1 u	2 u	4 u
Value	120	150	210
Total value	120 u	300 u	840 u

(a)
Total mass of bread flour
= 120 u + 300 u + 840 u
= 1260 u

1260 u = 8820

1 u = 8820 ÷ 1260 = 7

Total number of containers of X and Y used
= 1 u + 2 u
= 3 u
= 3 x 7
= 21 

(b)
Combined weight of all the bread flour in containers Y and containers Z
= 300 u + 840 u
= 1140 u

Difference between the combined weight of all the bread flour in containers Y and containers Z as compared to the bread flour in containers X
= 1140 u - 120 u
= 1020 u
= 1020 x 7
= 7140 g
= 7.14 kg 

Answer(s): (a) 21; (b) 7.14 kg