Three types of sugar, P, Q and R come in containers of 240 g, 420 g and 540 g respectively. Containers of P, Q and R are mixed together in the ratio 1 : 3 : 4 to obtain 25.62 kg of an assortment of sugar.

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

	P	Q	R
Number	1 u	3 u	4 u
Value	240	420	540
Total value	240 u	1260 u	2160 u

(a)
Total mass of sugar
= 240 u + 1260 u + 2160 u
= 3660 u

3660 u = 25620

1 u = 25620 ÷ 3660 = 7

Total number of containers of P and Q used
= 1 u + 3 u
= 4 u
= 4 x 7
= 28 

(b)
Combined weight of all the sugar in containers Q and containers R
= 1260 u + 2160 u
= 3420 u

Difference between the combined weight of all the sugar in containers Q and containers R as compared to the sugar in containers P
= 3420 u - 240 u
= 3180 u
= 3180 x 7
= 22260 g
= 22.26 kg 

Answer(s): (a) 28; (b) 22.26 kg