Q&A - P5 Math

[cimman]

G

happyheart:

one more please.


Q) There were 1600 pupils in a primary school. when the number of boys increased by 76 and the number of girls decreased by 4%, the total enrolment in the school increased by 3%. How many boys were there in the school at first?

if your child is willing to use algebra, here is an alternative way:
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[kyy]

Appreciate of someone can help explain how to solve this. Thanks.


Mr Noor paid $1740 for a total of 25 soccer balls and basketballs. Each soccer ball cost $84 and each basketball cost $48. How many of each type of ball did he buy.

[MathIzzzFun]

kyy:

Appreciate of someone can help explain how to solve this. Thanks.


Mr Noor paid $1740 for a total of 25 soccer balls and basketballs. Each soccer ball cost $84 and each basketball cost $48. How many of each type of ball did he buy.

variation of the \"chicken & cows\" question

$1740--> think total number of legs
25 soccer balls & basketballs --> think total number of animals
1 soccer ball cost $84 --> think 1 cow has 4 legs
1 basketball cost $48--> think 1 chicken has 2 legs
can u work it out?

cheers.

[kyy]

MathIzzzFun:

kyy:

Appreciate of someone can help explain how to solve this. Thanks.


Mr Noor paid $1740 for a total of 25 soccer balls and basketballs. Each soccer ball cost $84 and each basketball cost $48. How many of each type of ball did he buy.

variation of the \"chicken & cows\" question

$1740--> think total number of legs
25 soccer balls & basketballs --> think total number of animals
1 soccer ball cost $84 --> think 1 cow has 4 legs
1 basketball cost $48--> think 1 chicken has 2 legs
can u work it out?

cheers.

Managed to figure out. Thanks!

[zeemimi]

tianzhu:

zeemimi:

Pls help. Thank u.


The avg # of sit ups performed by 15 girls and some boys was 50.
The avg # of sit UPS performed by the girls was 80% of the avg # of situps performed by all the pupils.
The avg # of situps performed by the boys was 30% more than the avg # of situps performed by the girls.
A) what was the avg #of situps performed by the girls?
B) what% of the pupils were boys?

avg # of sit ups performed by 15 girls and some boys ------ 50.
avg # of sit UPS performed by the girls -------- 80% of 50 ------- 40
avg # of situps performed by the boys -------- 130% of 40 ------- 52

15*10 -------- 150
52 – 50 -------- 2
Number of boys ------ 150/2 ------- 75

75/90*100% -------- 83.33% (83 1/3)
Best wishes

thank you! problem taken from RGS 2011 SA2.

Could you explain this part?
15*10 -------- 150 (why 10?)
52 – 50 -------- 2
Number of boys ------ 150/2 (why?)

[tianzhu]

zeemimi:

thank you! problem taken from RGS 2011 SA2.

Could you explain this part?
15*10 -------- 150 (why 10?)
52 – 50 -------- 2
Number of boys ------ 150/2 (why?)

Hi

Good Morning.

Difference between avg # of sit UPS performed by the girls and avg # of sit
UPS performed by the total number of children ------ 10 (50-40)

The girls need 150 more (150*10) to bring up their average to 50.

These 150 sit ups come from the boys.

Difference in avg # of sit UPS performed by the boys and avg # of sit UPS performed by the total number of children ------ 2 (52-50)

Number of boys ----- 150/2 ----- 75.

Best wishes

[zeemimi]

Tks tianzhu!

[YumYum]

Hi, need help with this question:


1) Mr goh sold an equal number of apples and oranges. He sold the apples at $5 and $3 and the oranges at 7 for $4. At the end of the day, he collected $8 more from the sale of apples than the sale of oranges. How much money did he receive in total.

2) Aaron had a total of 336 Singapore and Malaysia stamps. He gave away 4/7 of the Singapore stamps and bought another 24 Malaysia stamps. As a result, the number of Malaysia stamps he had was 2/3 the number of singapore stamps left. How many more Singapore stamps than Malaysia stamps had he at first?

Thanks

[tianzhu]

YumYum:

Hi, need help with this question:


1) Mr goh sold an equal number of apples and oranges. He sold the apples at $5 and $3 and the oranges at 7 for $4. At the end of the day, he collected $8 more from the sale of apples than the sale of oranges. How much money did he receive in total.

2) Aaron had a total of 336 Singapore and Malaysia stamps. He gave away 4/7 of the Singapore stamps and bought another 24 Malaysia stamps. As a result, the number of Malaysia stamps he had was 2/3 the number of singapore stamps left. How many more Singapore stamps than Malaysia stamps had he at first?

Thanks

Hi

For Q1,a common multiple of 5 and 7 is 35.

7 groups of apples ------- 21

5 groups of oranges ------- 20

Difference ------- 1

He collected $8 more from the sale of apples than the sale of oranges.

(21+20)*8 ------- 328

For Q2, a neat way is to use MD.

Draw 7 boxes to show Singapore stamps.

He gave away 4 boxes, this leaves remainder of 3 boxes.

Draw a bar of length of 2 boxes less 24 to show Malaysian stamps in the end.

9 units ------- 336+ 24

1 unit ------ 40

Singapore stamps@first ------- 280

Malaysian stamps@first ------- 56

Please carry on from here.

Best wishes

[Udon]

Please help to explain the answer provided for this Question...Thanks.


Q1. What is the maximum number of wooden blocks measuring 0.03m by 0.02m by 0.06m that can be cut from a big block of wood measuring 12 cm by 11 cm by 15 cm？

Given answer:-

0.03m x 100 = 3 cm
0.02m x 100 = 2 cm
0.06m x 100 = 6cm

12 divided by 6 = 2
why 12/6, why not the \"length / length and the breadth / breadth and the height / height manner? :?:

11 divided by 2 = 5 R 1
15 divided by 3 = 5

2 x 5 x 5 = 50
The maximum number of wooden blocks that can be cut is 50.


Best Regards
Udon