Solution: suppose it takes x days to produce a part and 2 1-x days to produce b part, so that the produced parts are all matched.

(5*450)x=3*300(2 1-x)

2250x= 18900-900x

x=6

Type b: 2 1-6= 15.

6 days to produce a part, 2 1-6= 15 days to produce a part, so the parts produced are complete.