The average weekly number of toy trains produced by Factory B and C is 3357. The average weekly number of toy trains produced by Factory B and D is 6808. If Factory C produced ²₉ as many toy trains as Factory D each week, how many toy trains does Factory B produce weekly?
Total toy trains that Factory B and Factory C produced
= 3357 x 2
= 6714

Total toy trains that Factory B and Factory D produced
= 6808 x 2
= 13616

Number of toy trains produced by Factory C = 2 u
Number of toy trains produced by Factory D = 9 u

Factory B's toys + 2 u = 6714 --- (1)
Factory B's toys + 9 u = 13616 --- (2)

(2) - (1)
9 u - 2 u = 13616 - 6714
7 u = 6902
1 u = 6902 ÷ 7 = 986

Number of toy trains produced by C
= 2 u
= 2 x 986
= 1972

Number of toy trains produced by B
= 6714 - 1972
= 4742

Answer(s): 4742