Q&A - PSLE Math

[capricorn28]

Hi, the following are P5 maths questions. Hope somebody can help us on these.


1) After counting, Nessie found that 0.4 of the flowers in her garden are roses and 3/4 of the remaining flowers are tulips. The rest of the flowers are daisies. She has 30 more tulips than roses. How many daisies are there in the garden?

2) Denver would be 43 years old in a few years time. He would be 33.5 years old in half that time. He is 5 times his son’s age. How old is his son?

3) Mr Yap bought 4kg of durians and 3kg of apples for $50. If he bought 3kg of durians and 4kg of apples, he would pay $2 less. What is the cost of 1kg of durian?

4) The cost of tickets to the underwater world in Sentosa for 2 Adults and 3 Children is $92. The cost of 6 Adults and 4 Children is $196. What is the cost if Mr Tan goes with his wife and his 5 children?

Thank you.

[tianzhu]

After counting, Nessie found that 0.4 of the flowers in her garden are roses and 3/4 of the remaining flowers are tulips. The rest of the flowers are daisies. She has 30 more tulips than roses. How many daisies are there in the garden?


Hi

This question touches on Remainder concept or Part whole concept.
Using equivalent ratios, change 4:6 to 8:12.You may draw a MD or use the Branch method.

9units ---tulips
8 units ----roses
3 units ----daisies
1 unit ---- 30
3 units ----90

Mr Yap bought 4kg of durians and 3kg of apples for $50. If he bought 3kg of durians and 4kg of apples, he would pay $2 less. What is the cost of 1kg of durian?

Hi
DDDD AAA -------50
DDD AAAA ------48

D costs $2 more than A

4kg of durians and 3kg of apples for $50.

AAAA + 8 +3A ------ 50
A -------6
D ------8

You may draw MD with 1 bigger rectangle to show 1kg of durians and 1 smaller rectangle to show 1 kg of apples. Or you may choose to work with letters(alphabet) A and D to represent 1kg of apples and 1 kg of durians respectively once you become more familiar with such questions.

Best wishes

[tianzhu]

The cost of tickets to the underwater world in Sentosa for 2 Adults and 3 Children is $92. The cost of 6 Adults and 4 Children is $196. What is the cost if Mr Tan goes with his wife and his 5 children?


Hi

Q4 is similar to Q2.Once again, you may choose to work with MD or letters(alphabet), in this case A and C to represent adults and children.

AA CCC ----- 92
AAAAAA CCCC ------196

AAA CC ------98 (196/2)

A costs $6 more than C

CC +12+CCC ------92
C -------16
A ------22

AA ------44
CCCCC ------ 80
Total cost -------- 124

Best wishes

[tianzhu]

Denver would be 43 years old in a few years time. He would be 33.5 years old in half that time. He is 5 times his son's age. How old is his son?


Hi

I am not too sure if I've interpreted this question correctly.

1) Draw a rectangle block to represent present age of Denver

2) Add another rectangle block to (1) to show extension to 43 years old.

3) Draw same rectangle block as (1).Draw half the size of rectangle block as(2) to show future age of 33.5.

4) 43-33.5 ---9.5

5) Denver’s present age is 24.

Therefore his son is 24/5 ----4.8 years old. (Decimals still possible for age can be in years, months and days)

Check
Denver is now 24 years old.
19 years from now, he’ll be 43 years old.
In half of 19 years (9.5), he’ll be 33.5 years old

Please help to check calculations for these four questions as solutions done in a rush.

Best wishes

[capricorn28]

Hi tianzhu


Thank you for the quick and clear reply.
Have a good day.

[tianzhu]

capricorn28:

Hi tianzhu


Thank you for the quick and clear reply.
Have a good day.

Hi

You're welcome.

Best wishes

[kancheongmum]

Hi all need help

Raju drove at a constant speed from his house to Town B. On his way, he passed Town A. At 9.20 am he was 383 km from Town B and 205 km from Town A. At 12.50pm, he stopped at a petrol kiosk which was midway between Town A and Town B. At what speed did Raju drive before he came to the petrol kiosk? (ans 84km/h)
Thank you.

[Dharma]

kancheongmum:

Hi all need help

Raju drove at a constant speed from his house to Town B. On his way, he passed Town A. At 9.20 am he was 383 km from Town B and 205 km from Town A. At 12.50pm, he stopped at a petrol kiosk which was midway between Town A and Town B. At what speed did Raju drive before he came to the petrol kiosk? (ans 84km/h)
Thank you.

Distance = [205 + (383 - 205)/2]km = 294km
Speed = 294km/ 3.5hrs = 84km/hr

[tianzhu]

Hi Dharma


Good Morning

I think this question may cause problems to some students.

205km from Town A?
Is it 205km before Town A or after Town A?

To get 84km/h,a student has to interpret it as 205km before Town A, maybe it’s the intention of the question setter.

Best wishes

[ruohoo97]

Dharma:

kancheongmum:

Hi all need help

Raju drove at a constant speed from his house to Town B. On his way, he passed Town A. At 9.20 am he was 383 km from Town B and 205 km from Town A. At 12.50pm, he stopped at a petrol kiosk which was midway between Town A and Town B. At what speed did Raju drive before he came to the petrol kiosk? (ans 84km/h)
Thank you.

Distance = [205 + (383 - 205)/2]km = 294km
Speed = 294km/ 3.5hrs = 84km/hr

I didn't get it. the distance traveled from 9.20 to 12.50 should be (205+383)/2 -205=89 km, thus:
the speed will be 89/3.5=25.4km/h
???