Three types of rice flour, W, X and Y come in containers of 120 g, 150 g and 210 g respectively. Containers of W, X and Y are mixed together in the ratio 2 : 4 : 5 to obtain 18.9 kg of an assortment of rice flour.

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

	W	X	Y
Number	2 u	4 u	5 u
Value	120	150	210
Total value	240 u	600 u	1050 u

(a)
Total mass of rice flour
= 240 u + 600 u + 1050 u
= 1890 u

1890 u = 18900

1 u = 18900 ÷ 1890 = 10

Total number of containers of W and X used
= 2 u + 4 u
= 6 u
= 6 x 10
= 60 

(b)
Combined weight of all the rice flour in containers X and containers Y
= 600 u + 1050 u
= 1650 u

Difference between the combined weight of all the rice flour in containers X and containers Y as compared to the rice flour in containers W
= 1650 u - 240 u
= 1410 u
= 1410 x 10
= 14100 g
= 14.1 kg 

Answer(s): (a) 60; (b) 14.1 kg