Three types of bread flour, D, E and F come in containers of 120 g, 300 g and 420 g respectively. Containers of D, E and F are mixed together in the ratio 3 : 6 : 7 to obtain 45.9 kg of an assortment of bread flour.

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

	D	E	F
Number	3 u	6 u	7 u
Value	120	300	420
Total value	360 u	1800 u	2940 u

(a)
Total mass of bread flour
= 360 u + 1800 u + 2940 u
= 5100 u

5100 u = 45900

1 u = 45900 ÷ 5100 = 9

Total number of containers of D and E used
= 3 u + 6 u
= 9 u
= 9 x 9
= 81 

(b)
Combined weight of all the bread flour in containers E and containers F
= 1800 u + 2940 u
= 4740 u

Difference between the combined weight of all the bread flour in containers E and containers F as compared to the bread flour in containers D
= 4740 u - 360 u
= 4380 u
= 4380 x 9
= 39420 g
= 39.42 kg 

Answer(s): (a) 81; (b) 39.42 kg