Section 64(1) of the Income Tax Act, 1961 provides for the clubbing of income in the hands of the individual.
In this case Income earned for the year 2018-19 is Rs.10,00,000. This Income is earned by using Rs.300,000 of own Investment and Rs.200,000 which was gifted by husband.
So the Income which has to be clubbed in the hands of husband depends upon the ratio of Contribution in Capital. In this case ratio of Contribution of Wife and Husband is 3:2 respectively.
Therefore , Income to be clubbed in the hands of Husband is Rs.10,00,000 * 2/5 = Rs.4,00,000.