KBAT Permutation question from Selangor Trial Paper

I hope my explanation can help you understand this questions. Feel free to let me know if you find any mistake in my working or answer. Cheers

[mathew_pang]

sorry for my weird sound, got flu that day >.<"

[safo.o]

Thank you so much! Your videos have helped me since form 3! Am now going for spm this year and currently binge watching your videos. Hard for me to understand my school teachers hahah. Keep up the good work!

[hahahaha-tfln]

Congratulations for reaching 50000subscribers!

[tbs]

You look like our menteri pendidikan.. 😂

[Jacksonwang_]

Thank you teacher, I can more understand about this chapter clearly compare in other tuition class or in school

[hwennn]

could you please stream doing the MRSM 2018addmaths?

[dudezcrusher]

For the total, shouldn't it be 9x9x9x9? Coz 10 is like two spaces

[deanrogue]

Can u like do mrsm 2018 paper 1 and spm trials Selangor paper 1

[paanazmi]

i got using 9P1 x 9P3..this question quite tricky, i forgot to include 0 for next 3 numbers, so i put 9P1 x 8P3, which is wrong

[sw-ezsk]

Why the first digit for total can't (0)

[aimanalias]

the number 4536 also contain four different digit.. coincidence? i think not