Three types of bread flour, E, F and G come in containers of 100 g, 250 g and 350 g respectively. Containers of E, F and G are mixed together in the ratio 3 : 4 : 5 to obtain 21.35 kg of an assortment of bread flour.

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

	E	F	G
Number	3 u	4 u	5 u
Value	100	250	350
Total value	300 u	1000 u	1750 u

(a)
Total mass of bread flour
= 300 u + 1000 u + 1750 u
= 3050 u

3050 u = 21350

1 u = 21350 ÷ 3050 = 7

Total number of containers of E and F used
= 3 u + 4 u
= 7 u
= 7 x 7
= 49 

(b)
Combined weight of all the bread flour in containers F and containers G
= 1000 u + 1750 u
= 2750 u

Difference between the combined weight of all the bread flour in containers F and containers G as compared to the bread flour in containers E
= 2750 u - 300 u
= 2450 u
= 2450 x 7
= 17150 g
= 17.15 kg 

Answer(s): (a) 49; (b) 17.15 kg