I would be flying in Qatar Airways from Doha to Bangalore (India) and my check-in baggage allowance is 40 Kgs. Can I carry 3 bags within the limit of 40 kgs? Is there any limitation on the numbers of bags to be carried. Please help.
Yes, you can. The baggage rules page mentions that:
A single piece of checked baggage must not weigh more than 32kg (70lb). Any bags weighing more than 32kg (70lb) must be broken down such that each piece weighs less than 32kg (70lb).
No other restrictions are mentioned for flights to India, so you should be fine.