Difficult P.5 Math question...... 10 marks!!!

There are 7 girls in a bus.

----Each girl has 2 legs, so for now, there are 7x2 = 14 legs

Each girl has 7 backpacks.
In each backpack, there are 7 big cats.

----The number of big cats = 7x7x7 = 343
----Each cats has 4 legs,
----so the total number of legs of the big cats = 7x7x7x4 = 1372 legs

For every big cat there are 7 little cats.

----The number of little cats = 7x7x7x7 = 2401
----Each cats has 4 legs,
----so the total number of legs of the little cats = 7x7x7x7x4 = 9604 legs

Question: How many legs are there in the bus ?

----Therefore, there are 14 1372 9604 = 10990 legs in the bus.


Remarks:
If the legs of the bus driver is counted,
then there will be 10990 2 = 10992 legs in the bus.

Simply if there is only girls, then the total legs there are in the bus can be calculated as follows:
the total no of girls=7
the total no of the big cats=7*7*7=343
the total no. of small cats=343*7=2401
therefore the total no. of legs=7*2+(343+2401)*4=10983
but if the driver is counted then the answer must be 10983+2=10985(if it is an I.Q question)


2008-03-28 17:00:31 補充：
對唔住！禁錯機
therefore the total no. of legs=7*2+(343+2401)*4=１０９９０

but if the driver is counted then the answer must be 10990+2=10992(if it is an I.Q question)

70 leg
4x7+4x7+2x7=70
你look book please