Currently,  of the employees have a college degree; that is  out of the  employees. Let  be the number of additional employees who have a college degree:

All of the additional employees to be hired should have a college degree in order to double the percentage of employees with a college degree.

To begin with, we want to think about his problem conceptually. If Dmitri received a discount, we know our final answer will be higher than what he paid. Eliminate any choices that are less than . 

Next, we want to calculate how much the bike cost Dmitri before sales tax. To do this, we want to have a basic equation in front of us to ensure we are setting this up correctly.

or

The cost is what Dmitri paid, and the price is the listed sale price of the bike. We get  from knowing that sales tax is  and that Dmitri paid  of the price, plus  for sales tax. Recall that to change from a percent to a decimal, we just move the decimal point two places to the left.

So, we can rearrange the equation to solve for the sale price of the bike before sales tax...

We can round that to the nearest hundredth to get 

So, the sale price of the bike was ; however, do not choose that as your answer, because we are not done yet! We still need to find the original price of the bike. To do that, another equation will be helpful.

or

This means that the sale price is  of the original price, which is the same as saying it is  off.

We know  from above, so simply rearrange the equation, plug in the problem's values, and solve to find our final answer:

Again, we can round to the nearest cent to get our final answer of .

If  is 40% of , then .

Cube both sides to get

 is  of , or equivalently, 

 is  of .

 is 36% of , so

, or 

Square both sides:

 is  of , or, equivalently,  of .

This answer is not among the given choices.

 is 40% of , so .

Eqivalently, 

, and

 .

The question can be restated as

 is what percent of  ?

This can be answered as 

.

 is 20% of , so .

The question can be rewritten as

 is what percent of ?

The answer is found as follows:

 is 75% of , so 

and 

The question can be rewritten as

 is what percent of  ?

The answer is found as follows:

.

To calculate percent, we need to take one number and divide it by the other. We need to plan out the order carefully, though, because doing the division backwards will yield a trap answer. 

We need to find what percent of 5 40 is. It needs to be greater than 100%, because 40 is larger than five. This clues us in that 40 needs to be in our numerator. Perform the following to solve:

Don't stop just yet though, because to convert from decimals to percents we need to multiply by 100. This makes our final answer 800%. So, we can say the 40 is 800% of 5.

To find percents, simply divide the part by the whole. In this case, we are asked to find what percent 69 is of 108. Take 69 over 108 to find the answer.

Multiply by 100 and round to get our final answer

So, the answer is 64%.

We can set up an equation to solve this problem where  represents the orignal price:

That is, % of a number equals the  she saved. Now we just have to solve for :