I think 3:10 ratio is good
That is wrong.
amibroker automaticallly guesses the ratio based on price, but sometimes it is wrong.
the ratio is:
(number of shares after split) divided by (number of shares before split)
In this case:
number of shares after split = 10
number of shares before split = 1
(one Rs 10 share split into 10 Rs 1 shares)
Hence the ratio here is = 10/1 = 10
Similarly, in the case of bonus:
ratio=(total number of shares after bonus) divided by (number of shares before bonus)
The only differences is:
total number of shares after bonus = number of shares before bonus + number of bonus shares
For eg, take 2 for 3 (2:3) bonus, that is 2 shares given as bonus for every 3 shares held.
number of shares before bonus = 3
total number of shares after bonus = 3+2 =5
Hence, ratio=5/3= 1.66 (you may enter decimals too)