Q&A - PSLE Math

[tianzhu]

2DMommy:

2) 3 friends bought the same number of fruits each. Alan bought 5 oranges and some apples and paid $7.80. BOb bought 11 oranges and some apples and paid $9. How much did Chris pay if he bought only apples ?

Hi

9 – 7.8 ------ 1.2

11 – 5 ------ 6

1.2/6 ------ 0.2

An orange costs 20 cents more than an apple.

Chris ------ 7.8 - (5*0.2) ------- 6.8

or 9 - (11*0.2) ------ 6.8

Best wishes

[Shimmer]

Need help please Tianzhu !


1. A car and lorry which were 80k/m apart started to travel towards each other at the same time . The car 40km/h faster than the lorry. They went past each other after 2/5 hours.
A How far the lorry travel when it pass the car?
B Find the speed of lorry


2)A fan club had 150 members last year.This year, the no. of male reduces by 20% and the no. of female increase by 20%. As a result, there are as many male as females. How many people have this?


3)There were some balloons .25 burst and 10% flew. If there were 60% of balloons left, how many balloons were at first?

[alng]

Hi, please help me with this question. Thanks!


Jason has some chocolate and macadamia nuts cookies. If he sells 16 chocolate cookies and 4 macadamia nuts cookies a day, he would have 65 chocolate cookies left by the time all the macadamia nuts cookies are sold. If he sells 8 macadamia nuts cookies and 4 choclate cookies a day, he would have 289 chocolate cookies left by the time all the macadamia nuts cookies are sold. How many chocolate cookies does he have?

[tianzhu]

Shimmer:

Need help please Tianzhu !


1. A car and lorry which were 80k/m apart started to travel towards each other at the same time . The car 40km/h faster than the lorry. They went past each other after 2/5 hours.
A How far the lorry travel when it pass the car?
B Find the speed of lorry


2)A fan club had 150 members last year.This year, the no. of male reduces by 20% and the no. of female increase by 20%. As a result, there are as many male as females. How many people have this?


3)There were some balloons .25 burst and 10% flew. If there were 60% of balloons left, how many balloons were at first?

Hi

(1)

Start with a simple diagram.

In 60 minutes, the car covered 40 km faster than the lorry.

In 6 minutes, the car covered 4 km faster than the lorry.

In 24 minutes(2/5h), the car covered 16 km faster than the lorry.

80 – 16 ------ 64

64/2 ------ 32 km (distance travelled by lorry)

Speed of lorry ------ 32/2/5 ------ 80 km/h

(2)

M (last year) ------ 5 -------- 15
M (this year) ------ 4 ------ 12

F (last year) ------- 5 ------ 10
F (this year) ------- 6 ------ 12

As a result, there are as many male as females. Make the number of units for M(this year) and F(this year) the same.

25 units ------ 150

1 unit ------ 6

This year ------ 24 units ------ 24*6 ------- 144

(3)

25 ------- burst

1 unit ------- flew

9 units ------- 60%

3 units ------- 20%

15 units ------- 100%

5 units ------- 25

1 unit ------- 5

15 units ------- 5*15 --------75

Best wishes

[Winx5015]

Gd evening! Need some help for the following questions.


(1) Mr Lee sold 15% of his cupcakes on Monday. He sold 90 fewer cupcakes on Tuesday than on Monday. He then sold 70 fewer cupcakes on Wednesday than on Tuesday. On Thursday, he sold 330 cupcakes and found that he had half of his original number of cupcakes left. How many cupcakes did he sell altogether?

(2) There are some red and green beans in a container. If Ahmad removes 20 red beans, the ratio of the number of red beans to the number of green beans becomes 6:5. If Ahmad removes 10 green beans, the ratio of the number of red beans to the number of green beans becomes 4:3. How many beans are there in the container?

Thanks!

[tianzhu]

alng:

Hi, please help me with this question. Thanks!


Jason has some chocolate and macadamia nuts cookies. If he sells 16 chocolate cookies and 4 macadamia nuts cookies a day, he would have 65 chocolate cookies left by the time all the macadamia nuts cookies are sold. If he sells 8 macadamia nuts cookies and 4 choclate cookies a day, he would have 289 chocolate cookies left by the time all the macadamia nuts cookies are sold. How many chocolate cookies does he have?

Hi

Please refer to the solution for a similar question.

For your question

Scenario 1

CC -------- 8 units + 65
M ------- 2 units

Scenario 2

CC -------- 1 unit + 289
M ------- 2 units

7 units ------ 289 – 65 ------224

1 unit ------ 32

Number of CC -------- (8*32) + 65 ------- 321

Best wishes

http://farm6.staticflickr.com/5142/5614468685_555807d62e_z.jpg\">

[tianzhu]

Winx5015:

Gd evening! Need some help for the following questions.


(1) Mr Lee sold 15% of his cupcakes on Monday. He sold 90 fewer cupcakes on Tuesday than on Monday. He then sold 70 fewer cupcakes on Wednesday than on Tuesday. On Thursday, he sold 330 cupcakes and found that he had half of his original number of cupcakes left. How many cupcakes did he sell altogether?

(2) There are some red and green beans in a container. If Ahmad removes 20 red beans, the ratio of the number of red beans to the number of green beans becomes 6:5. If Ahmad removes 10 green beans, the ratio of the number of red beans to the number of green beans becomes 4:3. How many beans are there in the container?

Thanks!

Hi

These questions have been discussed before.

Please refer to page 652.

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&hilit=1000+students&start=6510

Best wishes

[jarenchuatw]

Need help with the Maths questions as attached - tried to load earlier but file was too big. http://i47.tinypic.com/imm5fp.jpg\">

[MathIzzzFun]

jarenchuatw:

Need help with the Maths questions as attached - tried to load earlier but file was too big. http://i47.tinypic.com/imm5fp.jpg\">

Hi

volume of tank --> 24 units
Large inlet pipe flow rate --> 24/3 = 8 units/h
Small inlet pipe flow rate --> 24/4 = 6 units/h
Outlet pipe flow rate --> 3/4 x 24/ 6= 3 units/h
When all pipes are turn on,
8 + 6 - 3 = 11 units/h --> tank filling at 11 units/h
Time to fill tank --> 24/11 x 60 min = 131 min (to nearest min)

cheers.

[jarenchuatw]

Wow, tks KGM, u have made the working very clear and easy to understand.


Got another question that needs your expertise http://i49.tinypic.com/vcryo8.jpg\">