calculating percentages?

Question

i wanna know how to calculate percentages
like ...how to know the percent of a number ?!
and the opposite ...well i dont know how to say it
but ill give examples
30% of 150 ?
15% of what is 30 ?!
what percent is 50 from 250 ?
and every possible way a Question might be about percentages

Answer 1

1.) 30% = 30/100 = 3/10



= (3/10) * 150

= 450/10

= 45



2.) 15% = 15/100 = 3/20

Let ' x ' be unknown.



(3/20) * x = 30

x = 30 * (20/3)

x = 600/3

x = 200



3.) Let ' x ' be unknown



(100/x) * 50 = 250

5000/x = 250

250 = 5000/x

x = 5000/250

x = 20%



Hope this helps

Bye !!

Answer 2

To find a percent of a number: convert the percent to decimal then multiply the number.

Example: 30% = 30/100 = .3 then 150 *.3 = 45 is your answer

To find how much percent is one number to another: use the first number divide by the second.

Example: 50 out of 250 is 50/250, that is .2, then convert that back to % which is like to muliply it by 100 to make it 20%.

To find the total number based on another number and percent: use the given number divede by the % to find the larger number.

Example: 50 is 20% of what number? Here we use 50/(20%) we know 20% is 0.2, now the expression is 50/.2 which gives us 250. So 50 is 20% of 250



Hope this helps :)

Answer 3

I don't know what you know so I'll just review :



To convert percent to decimal => move decimal point two places to the left. 30%= .30

To convert decimal to person => move decimal point two places to the RIGHT ~ .15 = 15%



Now the problems:

1. ( first example) turn all percents into decimals



2. change the world "of" into a multiplication sign.

30% of 150=> .30 X 150



3. then calculate.



4. when there is the word "what", you need a variable, let's say y. The word "is" is an equal sign.

second ex) 15% of what is 30.=> .15 X y = 30



5. Solve.



6. its the same for when your variable is the percent ( third ex.)

ex 3) 15% of what is 30?=> .15 X y = 30

Answer 4

one of the best ways to do percent is with the percent proportion: is over of = % over 100. 30% of 150 is...what ever is next to the word substitutes into the proportion...we know the percent, it is 30, so 30 goes over 100. Next to the word "of" is 150. 150 goes on the bottom of the proportion, left hand side. What is not filled out is your x. the equation reads: x over 150 = 30 over 100. cross multiply, then you will get your answer. the answer is: 45 use the % proportion for the rest of your problems

Answer 5

30% of 150 is 0.30 * 150 so it would be 45

15% of 30 is 0.15 * 30 = 4.5

50 from 250 is 50 divided by 250 = 0.2 ( 0.2 is the same as 20%)

Answer 6

im pretty sure its like this: examples:

30% of 150: 150 * .30 = 45

15% of 30: 30 * .15 = 4.5







like that :D