Q&A - P5 Math

[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

[MathIzzzFun]

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

Maximum number of blocks that can be cut is 54

http://i47.tinypic.com/1251jeq.png\">

cheers.

[imacsg]

Yazid and his class raced one another across a field. Midway through the race, 1/5 of Yazid’s classmates was running in front of him and 7/9 of the total number of pupils in the class was running behind him. What was the total number of pupils in the class including Yazid?


Can anyone solve the above question? Thanks

[tianzhu]

imacsg:

Yazid and his class raced one another across a field. Midway through the race, 1/5 of Yazid's classmates was running in front of him and 7/9 of the total number of pupils in the class was running behind him. What was the total number of pupils in the class including Yazid?


Can anyone solve the above question? Thanks

Hi

Is this a MCQ question or open ended question?

The answer is 36.

Best wishes

[MathIzzzFun]

imacsg:

Yazid and his class raced one another across a field. Midway through the race, 1/5 of Yazid's classmates was running in front of him and 7/9 of the total number of pupils in the class was running behind him. What was the total number of pupils in the class including Yazid?


Can anyone solve the above question? Thanks

Total number in class --> 9u
Pupils in front --> 2u-1, class mates --> 9u-1
so, 2u -1 : 9u-1 = 1 : 5
cross multiply/equalize:
10u-5 = 9u-1
1u--> 4
total number in class --> 36
cheers.

[imacsg]

MathIzzzFun,

Thanks, I also have 45 as the ans.
But the ans is 36, I think the ans is wrong.