Question

Professor Bartlett teaches a class of 11 students. She has a visually impaired student, Louise, who must sit in the front row next to her tutor, who is also a member of this class. Assume that the front row has eight chairs, and the tutor must be seated to the right of Louise. How many different ways can professor Bartlett assign students to sit in the first row?

Answer 1

@jim_thompson5910 help? :)

Answer 2

A big key phrase here is that "the tutor must be seated to the right of Louise", so if T is the tutor and L is Louise, then you can only have LT and NOT TL


So basically LT is one person since you can't a) separate the two AND b) you can't reorder it

Answer 3

so 6 spaces left right

Answer 4

So instead of 11 students to order, you really have 11-2+1 = 10 students to order since you're combining two students to form one "student'

Answer 5

10P6 maybe?

Answer 6

There are 8 chairs in the front, but 2 are taken up and combined into one "chair" so to speak. So there are really 8-2+1 = 7 "chairs" in the front row.

Answer 7

So it's really 10 P 7

Answer 8

so 10P7?

Answer 9

you got it

Answer 10

5040 ways?

Answer 11

5040 is 7! or 7 P 7, so no

Answer 12

whats 10P7 then?

Answer 13

10 P 7 = (10!)/((10-7)!)

Answer 14

604800= (10!)/(3!)?

Answer 15

you got it

Answer 16

finally thank you!

Answer 17

you're welcome