The average weekly number of toy trains produced by Factory S and T is 3240. The average weekly number of toy trains produced by Factory S and U is 6735. If Factory T produced ²₇ as many toy trains as Factory U each week, how many toy trains does Factory S produce weekly?
Total toy trains that Factory S and Factory T produced
= 3240 x 2
= 6480

Total toy trains that Factory S and Factory U produced
= 6735 x 2
= 13470

Number of toy trains produced by Factory T = 2 u
Number of toy trains produced by Factory U = 7 u

Factory S's toys + 2 u = 6480 --- (1)
Factory S's toys + 7 u = 13470 --- (2)

(2) - (1)
7 u - 2 u = 13470 - 6480
5 u = 6990
1 u = 6990 ÷ 5 = 1398

Number of toy trains produced by T
= 2 u
= 2 x 1398
= 2796

Number of toy trains produced by S
= 6480 - 2796
= 3684

Answer(s): 3684