Is weaning a child 24 or 30 months in the Qur’an.

The Quran says the mother’s responsibility to wean is two years –

S31:14 And We have enjoined upon man [care] for his parents. His mother carried him in weakness upon weakness, and his weaning is in two years…..

But the verse below say it is 30 months to wean –

S46:15 And We have enjoined on man doing of good to his parents; with trouble did his mother bear him and with trouble did she bring him forth; and the bearing of him and the weaning of him was thirty months….

The two verses above does not contradict each another if the responsibility of weaning and more time in weaning is required then a more convenient option for the mother is allowed by engaging a wet nurse –

S2:233 And the mothers should suckle their children for two whole years for him who desires to make complete the time of suckling; and their maintenance and their clothing must be borne by the father according to usage; no soul shall have imposed upon it a duty but to the extent of its capacity; neither shall a mother be made to suffer harm on account of her child, nor a father on account of his child, and a similar duty (devolves) on the (father’s) heir, but if both desire weaning by mutual consent and counsel, there is no blame on them, and if you wish to engage a wet-nurse for your children, there is no blame on you so long as you pay what you promised for according to usage; and be careful of your duty to Allah and know that Allah sees what you do.

So beyond the two year period of weaning a wet-nurse can be engaged if the mother is unable to give more sucklings to the child.