Q&A - PSLE Math

[Ender]

Thank you! I have one more question--

When she increased her spending by 30%, her savings decreased by 25%.

The above statement is mathematically saying this,
30% of $2500 = 1/4 of Saving at first

So "saving at first" is ________ ?

Hope you can solve from here.


Answer $5500

[wilburlim]

Question: Keira had $60 more than Jo. When Koera gave 2/5 of her money to Jo, Jo had $4 more than Kiera. How much money did Jo have initially?

[BigDevil]

vvv
A: 1715161
Subject: Math
Level: P6
Tags:
Source:
^^^

Question: Keira had $60 more than Jo. When Koera gave 2/5 of her money to Jo, Jo had $4 more than Kiera. How much money did Jo have initially?

From $60 more at first, to $4 lesser,
Keira would have given Jo $32.

2/5 -> $32
5/5 -> $80

Jo had $80 - $60 = $20 at first

[Nebbermind]

vvv
A: 1715161
Subject: Math
Level: P6
Tags:
Source:
^^^

Question: Keira had $60 more than Jo. When Koera gave 2/5 of her money to Jo, Jo had $4 more than Kiera. How much money did Jo have initially?

From $60 more at first, to $4 lesser,
Keira would have given Jo $32.

2/5 -> $32
5/5 -> $80

Jo had $80 - $60 = $20 at first

Alternatively, just draw models like any pri schoolers.
Before,
Keira
+60, which is also [U+12][U+12][U+12][U+12][U+12]

Jo


[u]After,
Keira
[U+12][U+12][U+12]

Jo
[U][U][U][U] + [U+12][U+12]

Therefore,

(Jo) 7U + 24 = (Keira) 3U + 36 + 4 (Jo has $4 more)
=> 4U = 16
=> 5U = 20

[SOS mum]

Hi, ps help. Many tks and God Bless:)

Yee Leng has some twenty cents and fifty cents coins.
2/3 of the total value of the twenty cents coins is the same as 1/2 of the total value of the fifty cents coins. If Yee Leng spends 4 fifty cent coins, the value of the twenty cents coins and the value of the remaining fifty cents coins will be the same. How many twenty cents coins does Yee Leng have?

The value of 2/3 twenty cent equals to half of fifty cents value, can be modelled as
Value of 20c = 3u
Value of 50c = 4u

Becoz 2/3 of 3u = 2u, which is half of the value of 50c coins. Therefore value of 50c is 2u x 2 = 4u

Thank u very much. Ender

Spent 4 fifty cent is just another way of saying he spent $2.

4u - 3u = $2
1u= $2

Value of 20c = 3u = $6

Number of 20c coins = 6/0.2 = 30 ##.

[doraemo]

hi, please help :

Keith and Mike had some chocolates in the ratio 2 : 5 When Mike gave away 40 chocolates to Keith and ate 20 chocolates himself, the ratio of keith’s chocolates to that of Mike’s chocolates became 2 : 1 How many chocolates did Mike have at first?

[doraemo]

hi , another one. please help.

Tom wants to make a square with rectangular cards each measuring 8 cm by 6 cm .
How many such rectangular cards must he use to make the smallest possible square?

[Nebbermind]

hi, please help :

Keith and Mike had some chocolates in the ratio 2 : 5 When Mike gave away 40 chocolates to Keith and ate 20 chocolates himself, the ratio of keith’s chocolates to that of Mike’s chocolates became 2 : 1 How many chocolates did Mike have at first?

Before,
K =>
M =>

After,
K => + 40 => [U+20][U+20]
M => [U+20] (coz K:M is 2:1)

But, M gave away 40 and ate 20
=>[U+20] + 40 + 20 = 5U
Therefore U = 20, and 5U = 100

[BigDevil]

vvv
A: 1715788
Subject: Math
Level: P6
Tags: LCM
Source:
^^^

hi , another one. please help.

Tom wants to make a square with rectangular cards each measuring 8 cm by 6 cm .
How many such rectangular cards must he use to make the smallest possible square?

LCM of 8, 6 -> 24

24 / 8 -> 3
24 / 6 -> 4
Number of cards -> 3 x 4 = 12

[doraemo]

Thank you, Nebbermind & BigDevil !!!!