Q&A - PSLE Math

[The Right Equation]

iamproudparents:

hi all, please help to enlighten us on these few maths questions, thanks alot.


1) the ratio of jim's savings to ken's savings is 1:2. jim received some money and his savings increased by 60%. what percentage of ken's money must be decreased so that their savings are equal?

http://i40.tinypic.com/6j3o1x.jpg\">

[The Right Equation]

iamproudparents:

hi all, please help to enlighten us on these few maths questions, thanks alot.


3) sandy started to drive from city Q to city P. at the same time, jack also started to drive in an opposite direction from city Q to city R. after travelling for 4 hours, sandy and jack were 620km apart from each other. if sandy's speed was 12km/h slower than jack's speed, what was jack's speed for the journey?

http://i40.tinypic.com/5qvrd.jpg\">

[The Right Equation]

iamproudparents:

hi all, please help to enlighten us on these few maths questions, thanks alot.


4) there were 846 glasses in a basket. some of the glasses were found to be broken and thrown away. of the remainder, 2/3 of the glasses were sold and 1/4 of the glasses was given away. there were 56 glasses left.

a) how many glasses were sold?

b) what fraction of the glasses in the basket was thrown away? give your answer in its simplest form.

http://i43.tinypic.com/29naxhe.jpg\">

[MathIzzzFun]

ozora:

MathIzzzFun:

[quote=\"ozora\"]http://i40.tinypic.com/4rvu3k.jpg\">

wonder is the answer 65 or 75?

a=70
b=75
c=40
d=30
e=35
f=45
m=n=65
p=115

cheers.

thanks. a bit loss for m and b.
could you possible provide start of the working for me to check.
thanks maths[/quote]one strategy is to look for angle pair that will yield the value of the 3rd in a triangle.
For eg

a+m= a+n= 135., this will give f=180-135=45,
this leads to
p=160-45=115
m=180-115=65
a= 135-65=70
d=100-70=30
b=105-30=75


cheers

[MathIzzzFun]

deleted ** duplicate posting

[Oldschool]

iamproudparents:

2) alice had some apples and bananas. 3/4 of the apples and 6/7 of the bananas are in good condition. 9/11 of the good fruits are apples. if the number of apples alice had was 522 more than bananas, how many fruits did alice have in all?

Hi,

Good Fruits
A : B : T
9 : 2 : 11
27 : 6: 33

¾ ---> 27/36 ---> 36U of apples at first
6/7 ---> 7U of banana at first

36U – 7U = 522
U = 18

Total = 36U + 7U = 43U = 43 x 18 = 774

Similar type of questions,
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?p=994887#p994887

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?p=996026#p996026

Regards

[concerned1970]

Someone pls help to solve the following ques


1) A farmer had 36 more ducks than chickens. 2/3 of the ducks and 3/5 of the chickens were sold. If 45 ducks and chickens were not sold. How many ducks and chickens did he have at first?

2) Mark and Joe have some marbles each. If Mark gives 8 marbles to Joe, both of them will have an equal number of marbles. If instead, Joe gives 6 marbles to Mark, Mark will have 5 times as many marbles as Joe. How many marbles does Joe have?

3) There are 36 pupils in the library. 2/3 of the boys and 1/4 of the girls wear specs. If 19 of the pupils wear specs, how many boys wear specs?

4) The ratio of Tom’s money to Sandra’s money was 8:5 at first. After Tom spent $12 and Sandra received $24 from her mother, the ratio became 2:3 How much did Sandra have at first?

[MathIzzzFun]

concerned1970:

Someone pls help to solve the following ques


1) A farmer had 36 more ducks than chickens. 2/3 of the ducks and 3/5 of the chickens were sold. If 45 ducks and chickens were not sold. How many ducks and chickens did he have at first?

Q1 & Q3 are similar -- various approaches - MD, unit/part, fractions..

AT first, Ducks --> 3u.......Chickens --> 5p
Left, Ducks --> 1u.....Chickens ---> 2p

total ---- 5p+36 = 3u -- (1)
left ----- 1u+2p = 45 --> 3u + 6p = 135

substituting 3u from (1)
5p+36+6p=135
p --> 9
u --> 27

At first,
ducks --> 81
chickens --> 45

cheers.

[MathIzzzFun]

concerned1970:

Someone pls help to solve the following ques



4) The ratio of Tom's money to Sandra's money was 8:5 at first. After Tom spent $12 and Sandra received $24 from her mother, the ratio became 2:3 How much did Sandra have at first?

using cross multiply/unit part -- visit Tianzhu's blog for the two ratio/two ifs questions.

At first, Tom : Sandra --> 8u : 5u
In the end, Tom : Sandra --> 8u - $12 : 5u + $24 = 2 :3

cross-multiply/equalize:

24u -$36 = 10u + $48
14u --> $84
1u --> $6

Sandra's money, at first --> 8 x $6 = $48

cheers.

[MathIzzzFun]

concerned1970:

Someone pls help to solve the following ques



2) Mark and Joe have some marbles each. If Mark gives 8 marbles to Joe, both of them will have an equal number of marbles. If instead, Joe gives 6 marbles to Mark, Mark will have 5 times as many marbles as Joe. How many marbles does Joe have?

If Mark gives 8 marbles to Joe, both will have equal marbles
--> Mark has 2 x 8 = 16 more marbles that Joe

If Joe gives 6 marbles to Mark, the difference will increase by 2 x 6 = 12 marbles, so Mark will have 16 + 12 = 28 marbles more than Joe

Mark --> 5u, Joe --> 1u
4u --> 28
1u --> 7

Joe's marbles --> 7 + 6 = 13

cheers.