What's the rule for working out percentages please?

Question

I forget every time! Could someone please help - I know it's something to do with dividing or multiplying by 100....

It's for my timesheet - if I work 40 hours, 70% of these hours are for a certain part of my role - how do I work out the number of hours?

Big thanks - will try to etch the formula on my brain!

Answer 1

Divide whatever it is by one hundred, then multiply it by the actual number of the percentage required! ! !

Answer 2

Percentage calculations are a way to compare different amounts in relationship to how many Parts Per Hundred (Per Centage) they each represent:

So in your question you KNOW that you worked 40 hours:

you require to know how much of this time is spent in a given role; knowing that 70 'parts in one hundred' of total were.

So writing this in mathematical notation

time in given role = [70/100 x 40]
= 7 x 4
= 28 hours

Now if you had to work out percentage LOSSES or GAINS you would use the Same Formula and add or subtract from STARTING Figure

e.g. How much is £5 a percentage increase on £3

5 - 3 = 2

So in numbers 3 Has increased by 2 or [{2/3} of original]


in percentage
{2/3 x 100}

= approximately 66.7%

Hope this helps -

GOOD LUCK

LIVE MATHS - - - - KEEP IT MATHS


If Original = P {Principal}
and Change = C

Percentage Change = {P ± C} / P x 100

Answer 3

you take 70% divide it by 100 and then times by the number you need to split apart

so 70/100 * 40 = 28 hours

For the other way round if you wanted to know what percentage of 40 hours was taken up through 28 hours of work then you do 28/40 * 100 = 70%

Answer 4

OK but this is the last time, so pay attention:

A) 50% means "half", 25% means "one quarter", 75% means "3 quarters"

so if you were told to do X for 75% of you time, that would be 3 quarters of your time (i.e. 30 hours out of 40) - you get this by doing 75*40/100=30

Here you need to do X for 70% of you time, so that's just a bit less than 75% (but you can check your calculations by thinking " if this were 75% then the answer would be 30 hours" you do 70*40/100 and you should get 28. If you get 2800 or 280 hours, you know something's wrong!

so in one day if you work 8 hours, how much of that should be spent on X? try to figure it out, but your rule of thumb should be "3 quarters of 8 hours is 6 hours, so 70% should be just a bit less than 6 hours" - then you calculate this: 8*70/100=5.6 hours.

hint 0.6 of an hour, given that there are 60 minutes in an hour is 0.6 * 60 = 36 minutes. Your rule of thum should be that 0.6 is just a bit more than 0.5 (=50%=half) so 0.6 of an hour should be just a bit more than 30 minutes.

Answer 5

change the percent to a decimal - so 70% = .70 then multiply .70 x 40 ( or whatever number you want) = 28 hr

another trick for simple percentages and numbers rounded to ten
70% of 10 is 7 then
take 7 x 4 (40hr divided by 10) = 28

Answer 6

Divide by one hundred and multiply by the percentage.

70% of 40 hours is
1% = .4 of an hour
70% is 70 x .4 = 28

xxR

Answer 7

40 X 70 / 100

Answer 8

Think of 70% as 7 out of 10. So, if you work 40, then 4*7=28.

Answer 9

The way I would work this is 40/100*70 = 28 hours. If the variables are slightly more challenging and you don't have a calculator to hand, I usually find out a tenth and work from there.

Answer 10

Change the percentage to a decimal by dividing by 100, which means moving the decimal point two places to the left or going to McDonald's (Golden Arch).

Now multiply the number you want to change by the decimal.

So: 70 / 100 = .7
.7 * 40 = 28

Answer 11

small value/ big value x 100

If a third of a cake was eaten
1/3 x 100=33%
so 70/100 x 40 = 28 hours