Indian Contract Act, 1872
45. Devolution of joint rights
When a person has made a promise to two or more persons jointly, then unless contrary intention appears from the contract, the right to claim performance rests, as between him and them, with them during their joint lives, and, after the death of any one of them, with the representative of such deceased person jointly with the survivor or survivors, and, after the death of the last survivor, with the representatives of all jointly.
A, in consideration of 5,000 rupees lent to him by B and C, promises B and C jointly to repay them that sum with interest on a day specified. B dies. The right to claim performance rests with B's representative jointly with C during C's life; and, after the death of C, with the representatives of B and C jointly.