Three types of bread flour, F, G and H come in containers of 120 g, 180 g and 240 g respectively. Containers of F, G and H are mixed together in the ratio 3 : 5 : 7 to obtain 35.28 kg of an assortment of bread flour.

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

	F	G	H
Number	3 u	5 u	7 u
Value	120	180	240
Total value	360 u	900 u	1680 u

(a)
Total mass of bread flour
= 360 u + 900 u + 1680 u
= 2940 u

2940 u = 35280

1 u = 35280 ÷ 2940 = 12

Total number of containers of F and G used
= 3 u + 5 u
= 8 u
= 8 x 12
= 96 

(b)
Combined weight of all the bread flour in containers G and containers H
= 900 u + 1680 u
= 2580 u

Difference between the combined weight of all the bread flour in containers G and containers H as compared to the bread flour in containers F
= 2580 u - 360 u
= 2220 u
= 2220 x 12
= 26640 g
= 26.64 kg 

Answer(s): (a) 96; (b) 26.64 kg