O-Level Additional Math

[Guan Hui]

Bonjour Oklor,
Heres the solution=)

[OK Lor]

Hi Sir,

Thanks.

[Guan Hui]

np=) good luck in your exams

[suiyuan]

Hi Teacher Guan Hui

Please help.

1)Mrs Lee has 2 daughters,Alice and Judy.The highest common factor and lowest common multiple of their ages are 3 and 168 respectively.If Alice is 3 years older than her sister, find her age.

2)The HCF and LCM of 270 and A are 18 and 5940 respectively. What is the value of A?

Thank you

[Guan Hui]

here you go

[OK Lor]

Hi Sir,

The number of arrangement of the word BOOKS if both O are to be placed together.

Answer is 4!2! or 4!?

Thanks.

[Guan Hui]

4!2!=)

[OK Lor]

Hi Sir,

Thanks. You mean there are two arrangements of OO? shouldn't it be 2!/2!=1? since there are identical, confuse. How about the number of arrangements of AABB? 4!/(2!2!) or 4!?

Thanks.

[Guan Hui]

eh wrong de previous 1 should be 4! onli I am so sorry=)
1st question:
4! if you group OO together so BOKS.
den x 2! because OO can be swap
den / 2! because O same as O
so is 4!

2nd question
AABB
4! cause 4 alphabets
/ 2! cause 2 As
/2! cause 2 Bs
4!/2!2!=3!

[OK Lor]

Hi Sir,

Thanks for the clarification and kind help.