Answer: 12,620,256
Step-by-step explanation:
Given: The camera shop socks eight different types of batteries and there re at least 31 batteries of each type.
Here we want to select r= 31 batteries from n= 8 kinds of batteries, then formula we use to find number of ways is 

Hence, the number of ways can a total inventory of 31 batteries be distributed among the eight different types = 12,620,256
The correct answer is A.
In order to find the correct answer in this one, you have to group all of the like terms. In this case, each term is unique with the exception of the x^2y^3 terms. Therefore, we need to check those first.
4x^2y^3 - (-5x^2y^3)
4x^2y^3 + 5x^2y^3
9x^2y^3
Since this term is included, we look for answers that involve this one. A is the only one that does. Plus, it includes each other term unchanged (which is good since there are no other like terms). Therefore, A is your answer.
Answer: 50
Step-by-step explanation: V= 1/3 x base x height
V= 1/3 (30)(5)
V=1/3(150)
V=50
Answer: y = 1/4x
Step-by-step explanation:
If the constant of proportionality is K, then:
y = kr
In which equation do we multiply x by 0.25 to get y?
1/4 = 0.25
Just type it into a calculator. (since there are three zeroes in 1000 just move the decimal point three times/spots to the left)
61.4/1000 = 0.0614