Nails are sold in packs of 40 for $1.30.

Screws are $0.07 each.

Since the total is $14.80, we must have a 0 in the hundredths place.  This means that the number of screws must be a multiple of 10 (otherwise it won't be a 0).  Now we are essentially dealing with screws in packs of 10 for $0.70.

Now we have 5 values of  to check.  If  is divisible by 7, then we have the right answer.

What we find is that for  is divisible by 7.

Thus our answer is 6 boxes or 240 nails.

The "is" in the question means "equal," so whatever comes before "is" must be equal to whatever comes after. We will find an expression for the information before "is" and an expression for the information after "is," and then we will set these two expressions equal.

Twenty percent of a number can be represented as 0.2n, because 20% expressed as a decimal is 0.2, and because twenty percent "of" a number means the product of that number and twenty percent.

Four greater than the product of a number and six means that we must first find the product of that number and six, and then increase this value by 4.

The product of a number and six means that we must multiply this number by six, which can be represented by 6n. Increasing 6n by 4 can be modeled by the expression 6n + 4, or 4 + 6n (because of the commutative property of addition).

Setting the two expressions equal gives us 0.2n = 4 + 6n .

The easiest way to solve this problem is to guess-and-check the answer choices. The equation that can be used to match the table will be correct.

We can see that the values in the table match the equation for each given value. Thus, this must be our answer.

We can also determine certain characteristics from the table itself. For example, as x increases, y(x) decreases. This tells us that there is likely a negative coefficient, which can help narrow down the answer options.

There are B+G total students in the elementary school class, so G out of B+G are girls.

Each term equals the previous term multiplied by .

The fifth term in the sequence is .

The sixth term in the sequence is thus .

Begin by rearranging the equation to solve for z:

This means that , which can be rewritten as .

Symbols may appear scary, but these problems are often easier than they first appear. Begin by taking the numbers you are given and replacing the letters in the equation with these numbers.

We can now solve the equation. Be sure to perform the operations within the parentheses (PEMDAS) first.

The correct answer is 512.

Begin by solving for : 

First, square both sides of the equation:

Now, solve for :

Now that we know that  is equal to 6, substitute 6 into the equation we need to solve:

Using the correct order of operations (PEMDAS), we find:

The answer is 19.

This is a simple substitution problem. Begin by setting the function  equal to :

Solve for :

A common mistake at this point is to believe that you have finished the question. We are given that . We must now substitute  for  and solve for :

Subtract 2 from both sides:

The answer is .