Question

A train time table must be compiled for various days of the week, so that two trains twice a day depart for three days, one train daily for two days, and three trains once a day for two days. How many diferent time table can be compiled?

Answer 1

1 train 3 days, number 2=>2 days
number 3 train=2
`(7!)/(3!2!2!)`
`(7*6*5*4*3*2)/(3*2*2*2)`
`30*7`
`210`.