It's 4. The factors of 12 are: 1,2,3,4,6,12. The factors of 20 are: 1,2,4,5,10,20.
Answer:
C
Step-by-step explanation:
P(n,r)=P(13,9)
=13!(13−9)!
=2.594592E+8
= 259459200
The altitude will be the geometric mean of the lengths, so

. The smaller leg is the hypotenuse of a right triangle sides 4 and

so the usual trig cliche, hypotenuse 8.
Answer: 8
Sense the books on sale for $5 and the CDs are for 10 he brought 1 CD. So he he brought 3 books because do 25-10 and get 15 and books are for $5. Hope that helped.