Answer:
I think it should be 
Step-by-step explanation:
When the question said area of the cube, I think it was supposed to be surface area, which would
where a is the length of one edge. Given that the length of one edge is 2x, we would plug in 2x to the equation to get
which would become
.
Answer: The director can choose first a lead singer and then a stand-in for the lead singer in 132 ways.
Step-by-step explanation:
Given : The total number of singers auditioning for the school musical.= 12
The director wanted choose first a lead singer and then a stand-in for the lead singer.
We use Permutations here because order of selecting the singers matters.
The number of permutations of selecting r things out of n things = 
Similarly , the number of ways to select 2 singers in an order from 12 singers


Hence, the director can choose first a lead singer and then a stand-in for the lead singer in 132 ways.
Answer: 80 in 5 seconds and 9 seconds for 144 feet
Step-by-step explanation:
16 x 5 =80
144 \ 16 =9
20 is no because its bigger than 15
11 yes because its less than 15
16 is no because its more than 15