Question: 21 is 30 percent of what number

Answer: 21 is 30 percent of 70

Step by step solution for calculating 21 is 30 percent of what number

We already have our first value 21 and the second value 30. 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 21 = 30% × Y

STEP 2 21 = 30/100× Y

Multiplying both sides by 100 and dividing both sides of the equation by 30 we will arrive at:

STEP 3 Y = 21 × 100/30

STEP 4 Y = 21 × 100 ÷ 30

STEP 5 Y = 70

Finally, we have found the value of Y which is 70 and that is our answer.

You can easily calculate 21 is 30 percent of what number by using any regular calculator, simply enter 21 × 100 ÷ 30 and you will get your answer which is 70

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Sample questions, answers, and how to

Question: Your friend has a bag of marbles, and he tells you that 30 percent of the marbles are red. If there are 21 red marbles. How many marbles does he have altogether?

Answer: 70 marbles.

How To: In this problem, we know that the Percent is 30, and we are also told that the Part of the marbles is red, so we know that the Part is 21.

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 21.

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

21 × 100 = 2100

In step two, we take that 2100 and divide it by the "Percent", which we are told is 30.

So, 2100 divided by 30 = 70

And that means that the total number of marbles is 70.


Question: A high school marching band has 21 flute players, If 30 percent of the band members play the flute, then how many members are in the band?

Answer: There are 70 members in the band.

How To: The smaller "Part" in this problem is 21 since there are 21 flute players and we are told that they make up 30 percent of the band, so the "Percent" is 30.

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.

21 × 100 = 2100

For step two, we divide that 2100 by the "Percent", which is 30.

2100 divided by 30 equals 70

That means that the total number of band members is 70.

Have time and want to learn the calculation?

Let's assume the unknown value is Y

First writing it as: 100% / Y = 30% / 21

Drop the percentage marks to simplify your calculations: 100 / Y = 30 / 21

Multiply both sides by Y to move Y on the right side of the equation: 100 = ( 30 / 21 ) Y

Simplifying the right side, we get: 100 = 30 Y

Dividing both sides of the equation by 30, we will arrive at 70 = Y

This leaves us with our final answer: 21 is 30 percent of 70

Percentage Table

21 is 30 percent of 70
21.01 is 30 percent of 70.033
21.02 is 30 percent of 70.067
21.03 is 30 percent of 70.1
21.04 is 30 percent of 70.133
21.05 is 30 percent of 70.167
21.06 is 30 percent of 70.2
21.07 is 30 percent of 70.233
21.08 is 30 percent of 70.267
21.09 is 30 percent of 70.3
21.1 is 30 percent of 70.333
21.11 is 30 percent of 70.367
21.12 is 30 percent of 70.4
21.13 is 30 percent of 70.433
21.14 is 30 percent of 70.467
21.15 is 30 percent of 70.5
21.16 is 30 percent of 70.533
21.17 is 30 percent of 70.567
21.18 is 30 percent of 70.6
21.19 is 30 percent of 70.633
21.2 is 30 percent of 70.667
21.21 is 30 percent of 70.7
21.22 is 30 percent of 70.733
21.23 is 30 percent of 70.767
21.24 is 30 percent of 70.8
21.25 is 30 percent of 70.833
21.26 is 30 percent of 70.867
21.27 is 30 percent of 70.9
21.28 is 30 percent of 70.933
21.29 is 30 percent of 70.967
21.3 is 30 percent of 71
21.31 is 30 percent of 71.033
21.32 is 30 percent of 71.067
21.33 is 30 percent of 71.1
21.34 is 30 percent of 71.133
21.35 is 30 percent of 71.167
21.36 is 30 percent of 71.2
21.37 is 30 percent of 71.233
21.38 is 30 percent of 71.267
21.39 is 30 percent of 71.3
21.4 is 30 percent of 71.333
21.41 is 30 percent of 71.367
21.42 is 30 percent of 71.4
21.43 is 30 percent of 71.433
21.44 is 30 percent of 71.467
21.45 is 30 percent of 71.5
21.46 is 30 percent of 71.533
21.47 is 30 percent of 71.567
21.48 is 30 percent of 71.6
21.49 is 30 percent of 71.633
21.5 is 30 percent of 71.667
21.51 is 30 percent of 71.7
21.52 is 30 percent of 71.733
21.53 is 30 percent of 71.767
21.54 is 30 percent of 71.8
21.55 is 30 percent of 71.833
21.56 is 30 percent of 71.867
21.57 is 30 percent of 71.9
21.58 is 30 percent of 71.933
21.59 is 30 percent of 71.967
21.6 is 30 percent of 72
21.61 is 30 percent of 72.033
21.62 is 30 percent of 72.067
21.63 is 30 percent of 72.1
21.64 is 30 percent of 72.133
21.65 is 30 percent of 72.167
21.66 is 30 percent of 72.2
21.67 is 30 percent of 72.233
21.68 is 30 percent of 72.267
21.69 is 30 percent of 72.3
21.7 is 30 percent of 72.333
21.71 is 30 percent of 72.367
21.72 is 30 percent of 72.4
21.73 is 30 percent of 72.433
21.74 is 30 percent of 72.467
21.75 is 30 percent of 72.5
21.76 is 30 percent of 72.533
21.77 is 30 percent of 72.567
21.78 is 30 percent of 72.6
21.79 is 30 percent of 72.633
21.8 is 30 percent of 72.667
21.81 is 30 percent of 72.7
21.82 is 30 percent of 72.733
21.83 is 30 percent of 72.767
21.84 is 30 percent of 72.8
21.85 is 30 percent of 72.833
21.86 is 30 percent of 72.867
21.87 is 30 percent of 72.9
21.88 is 30 percent of 72.933
21.89 is 30 percent of 72.967
21.9 is 30 percent of 73
21.91 is 30 percent of 73.033
21.92 is 30 percent of 73.067
21.93 is 30 percent of 73.1
21.94 is 30 percent of 73.133
21.95 is 30 percent of 73.167
21.96 is 30 percent of 73.2
21.97 is 30 percent of 73.233
21.98 is 30 percent of 73.267
21.99 is 30 percent of 73.3