In respect of a resident individual (or HUF), the position is as under :
If the only income is short-term capital gains on listed equity sold through a recognised equity exchange or redemption of equity-oriented mutual fund, then 15% tax is payable on such income only to the extent it exceeds the basic exemption limit. In your example, you have mentioned an income of Rs 50,000 in which case no tax will be payable on such income at all. If the other income is less than the basic exemption limit – Suppose the other income is Rs 210,000 and the basic exemption limit is Rs 2.50 lakh and the short-term capital gains as above is Rs 50,000 - Then the difference between the basic exemption limit (Rs 2.50 lakhs) and the other income (Rs 2.10 lakhs) is Rs 40,000, and this will be reduced from the short-term capital gains of Rs 50,000. The tax at 15% is payable on the difference of Rs 10,000 . For non-resident Indians or non individuals, this facility is not available and they pay the tax at 15% on the entire short-term capital gains as above, irrespective of the status of other income.
I am assuming that you (and not your tenant) pays the municipal taxes in respect of the rented out premises. If so then it is deductible from the rental amount while calculating the income from House property for the rented out property.
Painting the property can be considered as expenditure incurred for renewal of the property. There is no deduction as such for expenses incurred for renewal of the property but if you have taken a loan for the purpose of incurring expenses on renewal of the property then the interest payable on such borrowed capital will be allowed as a deduction. In other words if you had taken a loan for the purpose of painting your house then the interest payable on such a loan is deductible though the expense of painting itself is not deductible.