Q&A - PSLE Math

[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.

[starfish53]

Can anyone help with the following question?


A car and a lorry left Town at 1045 h and travelled towards Town Y which was 352 km away. The lorry took 4 hours to reach Town Y. The average speed of the car was 22 km/h faster than the lorry.
At what time did the card reach Town ?

Thanks in advance.

[Oldschool]

starfish53:

Can anyone help with the following question?


A car and a lorry left Town at 1045 h and travelled towards Town Y which was 352 km away. The lorry took 4 hours to reach Town Y. The average speed of the car was 22 km/h faster than the lorry.
At what time did the card reach Town ?

Thanks in advance.

Hi,

Speed of lorry = 352/4 = 88km/h

Speed of car = 22 + 88 = 110 km/h

Time taken for car to reach Y = 352 / 110 = 3.2 hrs or 3 hours 12 mins

Time is 1357hrs when car reach Y.

Regards

[starfish53]

Can anyone help me with the following question?


Steven gave 40% of his salary to his parents. He used 60% of the remaining money to pay his bills and he saved the rest. If the amount he gave to his parents was $800 more than the amount he saved, how much was steven's salary?

:thankyou: in advance.