Goh Pei Ming's son finishes PSLE, but has to solve 'final Math question' to unlock laptop - Mothership

It was inspired by one of the questions on this year’s PSLE Maths examination.

Goh Pei Ming's son has finally finished the Primary School Leaving Examination (PSLE) and is getting his laptop back.

In an Instagram post on Sep. 30, Goh congratulated his son for completing the milestone, adding that he was proud of him.

However, he set one final task for his son before his computer privileges were restored.

A post shared by Goh Pei Ming (@goh.pei.ming)

Goh, 44, is a Member of Parliament (MP) in Marine Parade–Braddell Heights GRC and is currently Senior Minister of State for Home Affairs as well as Social and Family Development.

Noting that he was unable to celebrate in person with his son as he was away on a business trip, he left a sheet of paper on his son's laptop.

It contained the "final Mathematics test" to be solved in order to obtain the password to his laptop.

"During the 25 days before PSLE, a boy set aside 4 hours each day for revision.

On days when he resisted the temptation to use his laptop during his revision time, he studied for the full 4 hours.

On the other days, he gave into temptation and studied for only 3 hours.

What is the least number of days he must have resisted using his laptop for his total revision time to be MORE THAN 90 hours?

He ended the note by telling his son to read carefully and expressed his love and pride once more.

In the comments, netizens congratulated Goh and his son for the milestone.

The answer, for those who are curious, is N = 16.