Three types of bread flour, W, X and Y come in containers of 160 g, 240 g and 360 g respectively. Containers of W, X and Y are mixed together in the ratio 2 : 5 : 7 to obtain 40.4 kg of an assortment of bread flour.

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

	W	X	Y
Number	2 u	5 u	7 u
Value	160	240	360
Total value	320 u	1200 u	2520 u

(a)
Total mass of bread flour
= 320 u + 1200 u + 2520 u
= 4040 u

4040 u = 40400

1 u = 40400 ÷ 4040 = 10

Total number of containers of W and X used
= 2 u + 5 u
= 7 u
= 7 x 10
= 70 

(b)
Combined weight of all the bread flour in containers X and containers Y
= 1200 u + 2520 u
= 3720 u

Difference between the combined weight of all the bread flour in containers X and containers Y as compared to the bread flour in containers W
= 3720 u - 320 u
= 3400 u
= 3400 x 10
= 34000 g
= 34 kg 

Answer(s): (a) 70; (b) 34 kg