Q&A - PSLE Math

[kiasu_student]

Hi there, as this is the kiasu parents website, me, being very kiasu, can ask if anyone knows how to derive formulas for summation equations excluding for i, i2, i3… as those r available online .And also how to find 1000! Or factorial.

[kiasu_student]

Thanks

[iamproudparents]

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[smileplease]

are these P6 questions? Post these at ‘Q&A-PSLE math questions’.

[sailorman]

nowadays still use logic only, cannot use algebra for P6?

[wahwah]

Hi,

Need some urgent help with the following math questions.

Mary spent 3/7 of her money on 6 marbles and 6 crystal balls and 1/4 of the remainder on 10 metal balls. Each marble cost 1/7 as much as a crystal ball. Each metal ball cost $0.90 more than a marble. How much money did Mary have at first?

The bookshelves in a library were arranged in rows of 8 shelves each.
The library bought another 4 shelves and rearranged the shelves into rows of 6 shelves each. After the rearrangement, the librarian found that he had 10 additional rows of shelves. How many shelves were there in the library in the end?

Many thanks in advance.

[MathIzzzFun]

wahwah:

Hi,

Need some urgent help with the following math questions.

Mary spent 3/7 of her money on 6 marbles and 6 crystal balls and 1/4 of the remainder on 10 metal balls. Each marble cost 1/7 as much as a crystal ball. Each metal ball cost $0.90 more than a marble. How much money did Mary have at first?

Cost of 1 marble --> 1 unit
Cost of 1 crystal ball --> 7 units

3/7 of money --> 6 units + 42 units = 48 units
1/7 of money --> 16 units, Total amount of money --> 112 units

Cost of 10 metal balls --> 1/4 of remainder = 1/4 x 4/7 of money = 1/7 of money
so, cost of 10 metal balls --> 16 units,
cost of 1 metal ball --> 1.6 units

1 metal ball cost $0.90 more than 1 marble
so, 0.6 unit --> $0.90
1 unit --> $1.50

Total amount of money --> 112 x $ 1.50 = $ 168

cheers.

[MathIzzzFun]

wahwah:

Hi,

Need some urgent help with the following math questions.

The bookshelves in a library were arranged in rows of 8 shelves each.
The library bought another 4 shelves and rearranged the shelves into rows of 6 shelves each. After the rearrangement, the librarian found that he had 10 additional rows of shelves. How many shelves were there in the library in the end?

Many thanks in advance.

10 additional rows of shelves --> 10 x 6 = 60 shelves
Total number of shelves removed from original number of rows (2 were removed from each row) = 60 - 4 = 56

At first, number of rows of shelves = 56/2 = 28

In the end, total number of shelves = 28 x 8 + 4 = 228

cheers.

[MathIzzzFun]

iamproudparents:

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James and Bond had $728 altogether. When James spent 1/4 of his money and Bond spend 2/3 of his, they found out that each had an equal amount of money left. How much did James have at first ?

Equal fraction/numerator method

http://www.tinyurl.com/mathizzzfun-equalfractions

Amount left :
3/4 James' money = 1/3 Bond's money
3/4 James' money = 3/9 Bond's money

James' money --> 4 units
Bond's money --> 9 units
Total --> 13 units --- $728
1 unit --> $56

Jame's money --> 4 x $56 = $224

cheers.

[wahwah]

MathIzzzFun,

Thanks so much!