Question:
Mr Kim had forgotten his 3-digit passcode for logging into his laptop. However, he remembered that the passcode contained three out of these four digits, 2, 4, 7 and 8. None of the digits were repeated. He tried 247 and 274 but both passcodes were incorrect. At most, how many more passcodes could he make?
Solution:
![P6 / CHIJ / 2019 / SA1 / Paper 2 – Q07 [3 marks]](https://i0.wp.com/sgprimaths.com/wp-content/uploads/2020/04/P6_CHIJ_2019_SA1_Paper2_Q07-Qns.jpg?resize=400%2C204&ssl=1)
