Q&A - P3 Math

[chloecube]

WCW:

u r welcome

this explanation was given by my teacher donkey yrs ago... i still can rem it hehehe...

i must be dreaming :oops: when the teacher is talking ....that's why i didnt know

[jwxh]

one book cost $4. one pen cost$3. Jack bought some books and pens for $41. He bought 5 more books than pens. How many books did he buy?

plse help! tks

[just888]

jwxh:

one book cost $4. one pen cost$3. Jack bought some books and pens for $41. He bought 5 more books than pens. How many books did he buy?

plse help! tks

Price of 5 books: $4 X 5 = $20

Remaining $ for the books and pen purchase: $41 - $20 = $21

Then guess and check:
3 books and 3 pens = ($3 X 4) + ($3 X 3) = $21

Answer: He brought total 3+5 = 8 books

[jedamum]

just888:

jwxh:

one book cost $4. one pen cost$3. Jack bought some books and pens for $41. He bought 5 more books than pens. How many books did he buy?

plse help! tks

Price of 5 books: $4 X 5 = $20

Remaining $ for the books and pen purchase: $41 - $20 = $21

Then guess and check:
3 books and 3 pens = ($3 X 4) + ($3 X 3) = $21

Answer: He brought total 3+5 = 8 books

Price of 5 books: $4 X 5 = $20

Remaining $ for the books and pen purchase: $41 - $20 = $21

1Group of (1book+1pen) = $4+$3=$7
21 / 7 = 3 groups ie 3books and 3pens

3books + 5(more) books=8books

[SAHM Chew]

A teddy bear cost as much as 3 toy clowns. During a sale, both toys were sold for $12 less. For the new prices, a teddy bear cost as much as 6 toy clowns. How much did the teddy bear cost before the sale? Can anyone provide me with the model and workings? Thanks

[MathIzzzFun]

SAHM Chew:

A teddy bear cost as much as 3 toy clowns. During a sale, both toys were sold for $12 less. For the new prices, a teddy bear cost as much as 6 toy clowns. How much did the teddy bear cost before the sale? Can anyone provide me with the model and workings? Thanks

Hi

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cheers.

[SAHM Chew]

Ok, i know already. Thanks

[jwxh]

tks everyone!

[Yerdua]

Hi hi,

Need help with this qn:
how many 4-digits numbers can you make using each of the following digits once: 2,2,5,9?

Is there a formula to get the answer fast or do we have to list all number out as working?

Thanks!

[MathIzzzFun]

Yerdua:

Hi hi,

Need help with this qn:
how many 4-digits numbers can you make using each of the following digits once: 2,2,5,9?

Is there a formula to get the answer fast or do we have to list all number out as working?

Thanks!

Hi

for p3, students are taught to list out the numbers.

for maths olympiad students, they will be taught the \"shortcut\"
number of 4 digit numbers = 4!/2!= 12
4! = 1 x 2 x 3 x 4, 2! = 1 x 2

Let the 4 digit number be ABCD, we can choose any of the 4 digits for A,
then we will be left with only 3 digits to choose for B, and then 2 choices for C and finally 1 choice for D
so, number of 4 digit numbers = 4 x 3 x 2 x 1 = 24
but since there are two \"2\"s, there will be double counting of the \"2\"s. The \"2\"s can be arranged in 2 ways so we have to divide by 2 to get the final answer --> 24/2 = 12

cheers.