# Question: 84 is 21 percent of what number?

## Step by step solution for calculating 84 is 21 percent of what number

We already have our first value 84 and the second value 21. Let's assume the unknown value is Y which answer we will find out.

As we have all the required values we need, Now we can put them in a simple mathematical formula as below:

STEP 1 84 = 21% × Y

STEP 2 84 = 21/100× Y

Multiplying both sides by 100 and dividing both sides of the equation by 21 we will arrive at:

STEP 3 Y = 84 × 100/21

STEP 4 Y = 84 × 100 ÷ 21

STEP 5 Y = 400

Finally, we have found the value of Y which is 400 and that is our answer. You can easily calculate 84 is 21 percent of what number by using any regular calculator, simply enter 84 × 100 ÷ 21 and you will get your answer which is 400 Here is a Percentage Calculator to solve similar calculations such as 84 is 21 percent of what number. You can solve this type of calculation with your values by entering them into the calculator's fields, and click 'Calculate' to get the result and explanation.

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## Sample questions, answers, and how to

Question: Your friend has a bag of marbles, and he tells you that 21 percent of the marbles are red. If there are 84 red marbles. How many marbles does he have altogether?

How To: In this problem, we know that the Percent is 21, and we are also told that the Part of the marbles is red, so we know that the Part is 84.

So, that means that it must be the Total that's missing. Here is the way to figure out what the Total is:

Part/Total = Percent/100

By using a simple algebra we can re-arrange our Percent equation like this:

Part × 100/Percent = Total

If we take the "Part" and multiply it by 100, and then we divide that by the "Percent", we will get the "Total".

Let's try it out on our problem about the marbles, that's very simple and it's just two steps! We know that the "Part" (red marbles) is 84.

So step one is to just multiply that Part by 100.

84 × 100 = 8400

In step two, we take that 8400 and divide it by the "Percent", which we are told is 21.

So, 8400 divided by 21 = 400

And that means that the total number of marbles is 400.

Question: A high school marching band has 84 flute players, If 21 percent of the band members play the flute, then how many members are in the band?

Answer: There are 400 members in the band.

How To: The smaller "Part" in this problem is 84 since there are 84 flute players and we are told that they make up 21 percent of the band, so the "Percent" is 21.

Again, it's the "Total" that's missing here, and to find it, we just need to follow our 2 step procedure as the previous problem.

For step one, we multiply the "Part" by 100.

84 × 100 = 8400

For step two, we divide that 8400 by the "Percent", which is 21.

8400 divided by 21 equals 400

That means that the total number of band members is 400.

## Another step by step method

Step 1: Let's assume the unknown value is Y

Step 2: First writing it as: 100% / Y = 21% / 84

Step 3: Drop the percentage marks to simplify your calculations: 100 / Y = 21 / 84

Step 4: Multiply both sides by Y to move Y on the right side of the equation: 100 = ( 21 / 84 ) Y

Step 5: Simplifying the right side, we get: 100 = 21 Y

Step 6: Dividing both sides of the equation by 21, we will arrive at 400 = Y

This leaves us with our final answer: 84 is 21 percent of 400