Three types of bread flour, P, Q and R come in containers of 120 g, 180 g and 240 g respectively. Containers of P, Q and R are mixed together in the ratio 1 : 2 : 3 to obtain 6 kg of an assortment of bread flour.

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

	P	Q	R
Number	1 u	2 u	3 u
Value	120	180	240
Total value	120 u	360 u	720 u

(a)
Total mass of bread flour
= 120 u + 360 u + 720 u
= 1200 u

1200 u = 6000

1 u = 6000 ÷ 1200 = 5

Total number of containers of P and Q used
= 1 u + 2 u
= 3 u
= 3 x 5
= 15 

(b)
Combined weight of all the bread flour in containers Q and containers R
= 360 u + 720 u
= 1080 u

Difference between the combined weight of all the bread flour in containers Q and containers R as compared to the bread flour in containers P
= 1080 u - 120 u
= 960 u
= 960 x 5
= 4800 g
= 4.8 kg 

Answer(s): (a) 15; (b) 4.8 kg