Income tax on Sale of House Property

Scenario  : 

Suppose Mr.A possess 10 cents of land and house property . 

Purchase date : 01/01/1991 @ consolidated cost of Rs.10 lakhs

Sales date 01/01/2020 @ consolidated cost of Rs.100 lakhs.

On what amount Income Tax will be assessed? 

GET VALUATION OF THE PROPERTY AS ON 01.04.2001 FROM VALUER OR FROM SUB-REGISTRAR OFFICE. IF IT IS 'X'. LONG TERM CAPITAL GAINS TAX WOULD BE 20% OVER  [100-X].

Sub scenario - what will be his Income tax liability..

a)If he buys another property of 100 lakhs before March 31st ?

WILL GET EXEMPTION U/S. 54 OF THE ACT; SO NO TAX LIABILITY

b) If he could not buy another property of the same value as on 31st March.

AS SAID ABOVE 20% + 4% CESS OVER THE LTCG.