How much gold ??

 This question was asked on Koun Banega Karodpati program.

Question 

How much gold is there in 18K  gold?

1.  100%

2. 50%

3.  25&

4.  75%

Answer 

K  in  18K gold stands for gold purity measurement.

24K is the purest gold.

To calculate the gold purity in 18K,

24K     ==   100 %

18K      ==    ???

==>>  ( 18 *  100   )   /   24

==>>  3/4  *  100

==>>    75  %