Answer:
d. 20
Step-by-step explanation:
The given question implies 5 permutation 2, i.e 
.
But,

= 
So that for 
, n = 5 and r = 2.

= 
= 
= 
Cancel out 3 and 2 with respect to the numerator and denominator.

= 5 * 4
= 20
Therefore,

= 20
So that the correct option is D.
Answer:
Step-by-step explanation:

I think you forgot to put the image in the question
Answer:
1. $8.
2. 48 counters.
Step-by-step explanation:
1. A pair of socks cost 20 - 2(6)
= $8.
2. let the number of counters in Box A and Box be be x.
Then the number of counters in Box B after the transfer is x + 1/2 x.
x + 1/2 x = 72
1.5 x = 72
x = 72 / 1.5
= 48.
Area= pi x r^2
hence,
pi x r^2 = 36 x pi
=> r^2=36
=>r= root over 36 = 6
in short...the radius is 6