Three types of rice flour, F, G and H come in containers of 160 g, 280 g and 400 g respectively. Containers of F, G and H are mixed together in the ratio 1 : 4 : 5 to obtain 19.68 kg of an assortment of rice flour.

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

	F	G	H
Number	1 u	4 u	5 u
Value	160	280	400
Total value	160 u	1120 u	2000 u

(a)
Total mass of rice flour
= 160 u + 1120 u + 2000 u
= 3280 u

3280 u = 19680

1 u = 19680 ÷ 3280 = 6

Total number of containers of F and G used
= 1 u + 4 u
= 5 u
= 5 x 6
= 30 

(b)
Combined weight of all the rice flour in containers G and containers H
= 1120 u + 2000 u
= 3120 u

Difference between the combined weight of all the rice flour in containers G and containers H as compared to the rice flour in containers F
= 3120 u - 160 u
= 2960 u
= 2960 x 6
= 17760 g
= 17.76 kg 

Answer(s): (a) 30; (b) 17.76 kg