1 project for B and J = 10 hrs

2 projects for B and J = 20 hrs

if 1 project for B = 15 hrs

then 1 project for J = 20 - 15 = 5 hrs.

Mr Lim: They are fine. Thank you.

Postman: How old are they now?

Mr Lim: The product of their 3 ages is 36. The sum of their ages is the same as my house number.

Postman: Err.. I canβt figure it out.

Mr LIm: Well, my eldest daughter is waiting for her letter now.

Postman: Oh, I got it. Thanks ]]>

the 2nd faster solution:

Yvonne + Rachel = From A (Starting pt) to B (Ending pt). 10 mins

Rachel = From B to A. 1 min

George + Rachel = From A to B. 7 mins

Rachel = From B to A. 1 min

Ben + Rachel = From A to B. 2 mins

Total time spent= 10 + 1 + 7 + 1 + 2 = 21 mins

Fastest solution:

Ben + Rachel = From A to B. 2 mins

Rachel = From B to A. 1 min

Yvonne + George = From A to B. 10 mins

Ben = From B to A. 2 mins

Ben + Rachel = From A to B. 2 mins

Total time = 2 + 1 + 10 + 2 + 2 = 17 mins.

Tada!

]]>Four friends need to cross a bridge.

They start on the same side of the bridge.

A maximum of two people can cross at any time.

It is night and they have just one lamp.

People that cross the bridge must carry the lamp to see the way.

A pair must walk together at the rate of the slower person:

* Rachel: - takes 1 minute to cross

* Ben: - takes 2 minutes to cross

* George: - takes 7 minutes to cross

* Yvonne: - takes 10 minutes to cross

The second fastest solution gets the friends across in 21 minutes.

The fastest solution takes 17 minutes. Can you work out how it is done? π

This is exactly the sort of question which a P4 kid will answer with ease but on the other hand will leave an adult hopelessly stumped.

In any case, probably being a P4 kid at heart, Miss Loi believes she has the full answer and explanation (and just to prove that she *really* does know: you'll just have to imagine you're the postman who's supposed to know it all - right? RIGHT? π ) but she shan't reveal it now coz she would like to pose this question to others in the meantime π

Wow the answer really JUMPED right out from the screen! Hahaha ...

]]>Product Sum

1 1 36 = 38

1 2 18 = 21

1 3 12 = 16

1 4 9 = 14

1 6 6 = 13

2 2 9 = 13

2 3 6 = 11

3 3 4 = 10

Can you see something there?

]]>14 (= 1 + 4 + 9), 16 (= 1 + 3 + 12) or 21 (= 1 + 2 + 18)

but does that help?

The last reply that enlightened the postman is the statement that stumps me. What's the link between the eldest daughter's 'age' & 'letter'?

]]>