Her exceptional achievement has shocked her brother, who had previously resorted to using money as reinforcement to help his little sister study harder.
The man, known only as Dayo on Twitter, said that he had chosen to use financial incentives to encourage his younger sister.
For each course she receives an A, he promised to give her 2,000 naira.
To his great astonishment, the little sister ended the term with the highest grade in her class, earning 15 As.
The man who now owes his younger sister N30,000 has expressed regret online about how he will pay the debt.