Three types of bread flour, X, Y and Z come in containers of 160 g, 200 g and 280 g respectively. Containers of X, Y and Z are mixed together in the ratio 2 : 5 : 7 to obtain 26.24 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	2 u	5 u	7 u
Value	160	200	280
Total value	320 u	1000 u	1960 u

(a)
Total mass of bread flour
= 320 u + 1000 u + 1960 u
= 3280 u

3280 u = 26240

1 u = 26240 ÷ 3280 = 8

Total number of containers of X and Y used
= 2 u + 5 u
= 7 u
= 7 x 8
= 56 

(b)
Combined weight of all the bread flour in containers Y and containers Z
= 1000 u + 1960 u
= 2960 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
= 2960 u - 320 u
= 2640 u
= 2640 x 8
= 21120 g
= 21.12 kg 

Answer(s): (a) 56; (b) 21.12 kg