making a fraction into percentage

[defeated_soldier]

Hi,

i was looking at how close and quickly i can make a fraction into percentage

For example,

11.5/21 = how much percentage ?

available answers :

(a) 55 % (b)59%


My approach:

what i did is 11.5 is approximately 12
so 11.5/21 is approximately 12/21

12/21 is > 1/(21/12) >1/2

and 1/2 =50%

so 11.5/21 >50%

but still there are 2 answers which are greater than 50% in the answers given by (a) and (b)

How do i decide now ?



What i am expecting is , to get a quicker tips from you to choose the best option given .....i am not going to divide the fraction and convert into percentage really .

can you provide me some quicker tips ?

 

[Mrspi]

Hi,

i was looking at how close and quickly i can make a fraction into percentage

For example,

11.5/21 = how much percentage ?

available answers :

(a) 55 % (b)59%


My approach:

what i did is 11.5 is approximately 12
so 11.5/21 is approximately 12/21



12/21 is > 1/(21/12) >1/2

and 1/2 =50%

so 11.5/21 >50%

but still there are 2 answers which are greater than 50% in the answers given by (a) and (b)

How do i decide now ?



What i am expecting is , to get a quicker tips from you to choose the best option given .....i am not going to divide the fraction and convert into percentage really .

can you provide me some quicker tips ?

Well, gee...I don't know AT ALL how you would decide "most quickly"

But here's something really basic which might help you:

part / whole = percent / 100

I have no clue what you mean by "11.5/21"

If you could clarify what you mean, some of us could probably assist you.

 

[Denis]

"12/21 is > 1/(21/12)" : NO; 12/21 is = 1/(21/12)

"so 11.5/21 > 50%" : OK; but you know that right away, since 11.5 * 2 = 23 > 21