Capital Gain Querry

Interest on money borrowed to purchase a house can't be included in cost of acquisition as it is allowed u/s 24

I sold a property for Rs.48.00 lakh out of which capital gain is Rs.21.51 lakh. 

Kindly clarify the following :-

For me to avoid paying the 20% tax on capital gains should I invest the entire amount of Rs.48.00 lakh in capital gain bonds or only the taxable amount of Rs.21.51 lakh

If the property sold is house property, only capital gain amount is to be invested in CG bonds, as per u/s. 54 of the act.