Tim must choose 4 graphic novels out of a collection of 13 to take on vacation. in how many ways can he select the graphic novels? a. 28,561 b. 17,160 c. 715 d. 52

715 ( C )

Explanation:

C (13,4) = (13!)/(4!*9!)

So it can be done on the calculator by 13C4  

13! = 13 x 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

4! = 4 x 3 x 2 x 1

9! = 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1

13 x 12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 / ( 4 x 3 x 2 x 1 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 )

6,227,020,800 / 8,709,120

=715

So the correct answer is C, 715

b

step-by-step explanation:

calculate the scale factor as the ratio of corresponding sides, image to original, that is

scale factor = = = = 1

(a) the volume of the cone is 20/3 in3

hence, option a is correct.