Three types of bread flour, R, S and T come in containers of 240 g, 420 g and 600 g respectively. Containers of R, S and T are mixed together in the ratio 1 : 3 : 5 to obtain 40.5 kg of an assortment of bread flour.

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

	R	S	T
Number	1 u	3 u	5 u
Value	240	420	600
Total value	240 u	1260 u	3000 u

(a)
Total mass of bread flour
= 240 u + 1260 u + 3000 u
= 4500 u

4500 u = 40500

1 u = 40500 ÷ 4500 = 9

Total number of containers of R and S used
= 1 u + 3 u
= 4 u
= 4 x 9
= 36 

(b)
Combined weight of all the bread flour in containers S and containers T
= 1260 u + 3000 u
= 4260 u

Difference between the combined weight of all the bread flour in containers S and containers T as compared to the bread flour in containers R
= 4260 u - 240 u
= 4020 u
= 4020 x 9
= 36180 g
= 36.18 kg 

Answer(s): (a) 36; (b) 36.18 kg