Q&A - PSLE Math

[Ender]

Can anyone help me with these questions? Thank you

14) Straigth away we were givien Catherine swam 28 mins and Betty 37 mins (9 minute longer) That means it's either choice 1 or 2.

Betty ran 7.5km/h, that translate to 15/7.5 = 2hrs, which is 120mins. and Catherine is 8 minutes l̶o̶n̶g̶e̶r̶ faster, i.e. 1̶2̶8̶ 112 minutes.
Answer (̶1̶)̶ (2) ###

Note: Strikethrough the original mistake.

15)
Diameter is 4cm
One row, he can cut = 60/4 = 15 circles

one column he can cut h/4 circles

Total number of circles he can cut = 15 X h/4 = 3.75h ###

26)
AD : DC =? 3 : 2 => 6u and 4u respectively
AE = 3u and DF = 2u

Area of rectangle = 6u X 4u = 24u²

Area of Triangle = 1/2 X 3u X 2u = 3u²

Fraction 3u²/24u² => 1/8 ###

[sushi88]

Q14, Catherine was 8 minutes faster than Betty, not longer.

[Ender]

Q14, Catherine was 8 minutes faster than Betty, not longer.

My bad, read the question wrongly.

Answer should be 2) then,

[BigDevil]

Can anyone help me with these questions? Thank you

13)
(43+∠CDE) + (48 +∠DCE) = 180
∠CDE + ∠DCE = 180 - 43 - 48 = 89

(∠CDE + ∠DCE) + ∠CED = 180
89 + ∠CED = 180
∠CED = 180 - 89 = 101 ##

∠CED = 43 + 48 = 91

Ender made a calculation error.
180 - 89 = 91

[Ender]

Can anyone help me with these questions? Thank you

13)
(43+∠CDE) + (48 +∠DCE) = 180
∠CDE + ∠DCE = 180 - 43 - 48 = 89

(∠CDE + ∠DCE) + ∠CED = 180
89 + ∠CED = 180
∠CED = 180 - 89 = 101 ##

∠CED = 43 + 48 = 91

Ender made a calculation error.
180 - 89 = 91

Thanks for the correction... Reminds me to use calculator next time..

[wilburlim]

Hello I need help for this question:

A survey carried out by a school revealed that 1185 of the pupils walk to school every day. 70% of the remaining pupils go to school by bus while the rest of the pupils go to school by car. Given that 1/5 of the school enrolment goes to school by car, what is the enrolment of the school?

[Ender]

Let pupils that goes to school by bus and car altogether be 100u,
Then those by bus will be 70u and
by cars will be 30u

30u (by cars) are 1/5 of the schools enrolment.
Therefore school enrolment is = 30u X 5 = 150u

Those who walk = 150u - 100u = 50u
50u = 1185
u = 23.7

school enrolment = 150u = 3555 ###

[SOS mum]

Hi, ps help. Many tks and God Bless:)

Yee Leng has some twenty cents and fifty cents coins.
2/3 of the total value of the twenty cents coins is the same as 1/2 of the total value of the fifty cents coins. If Yee Leng spends 4 fifty cent coins, the value of the twenty cents coins and the value of the remaining fifty cents coins will be the same. How many twenty cents coins does Yee Leng have?

[Ender]

Hi, ps help. Many tks and God Bless:)

Yee Leng has some twenty cents and fifty cents coins.
2/3 of the total value of the twenty cents coins is the same as 1/2 of the total value of the fifty cents coins. If Yee Leng spends 4 fifty cent coins, the value of the twenty cents coins and the value of the remaining fifty cents coins will be the same. How many twenty cents coins does Yee Leng have?

The value of 2/3 twenty cent equals to half of fifty cents value, can be modelled as
Value of 20c = 3u
Value of 50c = 4u

Becoz 2/3 of 3u = 2u, which is half of the value of 50c coins. Therefore value of 50c is 2u x 2 = 4u

Spent 4 fifty cent is just another way of saying he spent $2.

4u - 3u = $2
1u= $2

Value of 20c = 3u = $6

Number of 20c coins = 6/0.2 = 30 ##.

[wilburlim]

Thank you! I have one more question--

Mr Chan spent $2500 of her salary and saved the rest. When she increased her spending by 30%, her savings decreased by 25%. How much was her salary?