Three types of bread flour, N, P and Q come in containers of 240 g, 360 g and 420 g respectively. Containers of N, P and Q are mixed together in the ratio 1 : 3 : 6 to obtain 19.2 kg of an assortment of bread flour.

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

	N	P	Q
Number	1 u	3 u	6 u
Value	240	360	420
Total value	240 u	1080 u	2520 u

(a)
Total mass of bread flour
= 240 u + 1080 u + 2520 u
= 3840 u

3840 u = 19200

1 u = 19200 ÷ 3840 = 5

Total number of containers of N and P used
= 1 u + 3 u
= 4 u
= 4 x 5
= 20 

(b)
Combined weight of all the bread flour in containers P and containers Q
= 1080 u + 2520 u
= 3600 u

Difference between the combined weight of all the bread flour in containers P and containers Q as compared to the bread flour in containers N
= 3600 u - 240 u
= 3360 u
= 3360 x 5
= 16800 g
= 16.8 kg 

Answer(s): (a) 20; (b) 16.8 kg