In previous works we establish a mathematical expression like the time dilation expression, a time dilation-like (time dilation is valid in relation to a preferred frame) and considered by the standard formulation the time dilation expression, valid reciprocally. This conundrum has also been previously eliminated. Now we show how we can use this time dilation-like expression eliminating the twin paradox conundrum that standard formulation is unable to accomplish, since erroneously attribute the meaning of a reciprocal relation to the ageing of the twins. Therefore, we calculate the classic example of the twins whatever the frames considered. The twin that returns is the younger because the cumulative effect of the ageing is not reciprocal. Since the time dilation like exist and can be used, originating the idea of "seeing the other twin ageing slower"- the origin of the conundrum. This cannot subsist because the relation between ageing is a relation between proper times. The time dilation-like expression is a relation between proper times only for the preferred frame.