# Math Help - how to find a number when a percent of it is given

1. ## how to find a number when a percent of it is given

If u could help I just need to figure out how to find a number when a percent og it is given. Thanks 4 all your help.

2. Originally Posted by tiffel23
If u could help I just need to figure out how to find a number when a percent og it is given. Thanks 4 all your help.
Example: 20% of a number is 12. What is the number?

Let x = the number

$.20x=12$

$x=\frac{12}{.20}$

$x=60$

3. ## think I figured it but not sure

I think I figured it out buit not sure some I came up with really long answers so I rounded up if u could chk these out n let me know what u think that would b great thanks so... much. I included my answers. the numbers in blue are my answers

1. 64 is 8% of 800
2. 27 is 19% of 142.11
3. 42 is 42% of 100
4. 64 is 35% of 182.86
5. 53 is 68% of 77.94
6. 12 is 22% of 54.54
7. 94 is 77% of 122.08
8. 86 is 150% of 57.33
9. 34 is 16% of 212.5
10. 194 is 12.5% of 1552
11. 260 is 71% of 366.197
12. 984 is 150% of 656
13. 475 is 300% of 158.33
14. 645 is 560% of 115.18

4. Hello, tiffel23!

I need to figure out how to find a number when a percent of it is given.

Here's one approach to this problem . . .

Example: 40% of a number is 140. .What is the number?

$\text{It says: }\;\underbrace{\text{40 percent}}_{0.40} \underbrace{\text{ of }}_{\times} \underbrace{\text{ a number }}_N \underbrace{\text{ is }}_{=}\underbrace{140}_{140}$

And there is our equation! . . . . $0.40N \:=\:140$

Therefore: . $N \:=\:\frac{140}{0.40} \;=\;350$

5. Rite if u mean like, 5 is 10% of the a number, what is the number?

Then this is how you do it,

Using my example:

a percentage means 'how many hundredths of the inital number you have'

i.e. 1 is one hundredth of 100, (there are 100 1's in 100)

so 1 is 1% of 100, because you have 1 hundredth.

So if you given the percentage, in my example it was 10% you know you have 10 one hundredths.

So logically if you divide your amount (5 in this case) by 10 you will get one hundredth, (in this case it comes to 0.5)

then if that is one hundredth of the total you are after, you just times is by 100, giving you 50, and that is the answer. (5 is 10% of 50)

METHOD SUMMERY:

6 is 15 percent of a number, what is the number?

first divide by the percentage:

6/15 = 0.4

then times by 100

0.4*100 = 40

so 6 is 15 percent of 40.

i Hope this helped, good luck

6. Oh and i forgot to add:

1. 64 is 8% of 800 (correct)
2. 27 is 19% of 142.11 (correct)
3. 42 is 42% of 100 (correct)
4. 64 is 35% of 182.86 (correct)
5. 53 is 68% of 77.94 (correct)
6. 12 is 22% of 54.54 (correct)
7. 94 is 77% of 122.08(correct)
8. 86 is 150% of 57.33(correct)
9. 34 is 16% of 212.5(correct)
10. 194 is 12.5% of 1552(correct)
11. 260 is 71% of 366.197(correct)
12. 984 is 150% of 656(correct)
13. 475 is 300% of 158.33(correct)
14. 645 is 560% of 115.18(correct)

well done