Q&A - PSLE Math

[YumYum]

MathIzzzFun:

YumYum:

Hi, can someone pls help with this question:


Father has given Claire and Jane each a certain amount of money to spend. If Claire spends $30 each day and Jane spends $20 each day, Claire would have $100 left by the time Jane spends all her money. If Claire spends $20 each day and Jane spends $30 each day, Claire would have $600 left by the time Jane spends all her money. Find the total amount of money given to Claire. thks.

Similar questions here-


http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&start=8940

cheers.

thank you

[YumYum]

MathIzzzFun:

YumYum:

Hi, can someone pls help with this Qn? thks


http://i34.tinypic.com/14jchs9.jpg\">

For every length of 350cm(7 x 50cm ropes, 5 x 70 cm rope)

Number of black flags -> 7 x 2= 14
Number of white flags -> 5 x 5 = 25
25-14=. 11 --> 11 more white flags
total --> 39 flags

number of 350cm groups
-> 220 ÷ 11 = 20

total number of black and white flags --> 20 x 39 = 780

cheers.

Thank you for yr help :xedfingers:

[iamproudparents]

hi there anybody can assist? thanks alot in advance.


1) after a quiz, anna and her friends calculated the average of their scores. they noted that if anna could get 18 more marks, their average score would be 82. if anna had scored 6 marks less, their average score would be 76. how many friends participated with anna in the quiz?

2) at 12 noon, a lorry driver left malacca for desaru travelling at a constant speed. at 2pm, a motorcylist also left malacca for desaru, travelling along the same route at a constant speed. the motorcylist overtook the lorry driver at 5pm. the speed of the motorcylist was 34 km/h faster than that of the lorry driver. find the speed of the lorry driver in km/h.

3) stanley used 4/7 of his money to buy 9 pens. he wanted to buy another 7 such pens but was short of $1.20. how much money did stanley have at first?

4) sam is 5 times as old as his sister. in 10 years time, sam will be 12 years less than thrice his sisters age then. how much older is sam than his sister?

[Oldschool]

iamproudparents:

hi there anybody can assist? thanks alot in advance.


1) after a quiz, anna and her friends calculated the average of their scores. they noted that if anna could get 18 more marks, their average score would be 82. if anna had scored 6 marks less, their average score would be 76. how many friends participated with anna in the quiz?


Original total + 18 = 82(F+1)

Original total - 6 = 76(F+1)

18 = 6F

F = 3 (Ans)

2) at 12 noon, a lorry driver left malacca for desaru travelling at a constant speed. at 2pm, a motorcylist also left malacca for desaru, travelling along the same route at a constant speed. the motorcylist overtook the lorry driver at 5pm. the speed of the motorcylist was 34 km/h faster than that of the lorry driver. find the speed of the lorry driver in km/h.


Time taken by lorry = 5hrs
Time taken by motorcycle = 3hrs

At the time of overtaking, both have travelled the same distance = S x T

5L = 3(L+34)

L = 51km/h (ans)


3) stanley used 4/7 of his money to buy 9 pens. he wanted to buy another 7 such pens but was short of $1.20. how much money did stanley have at first?


7U of money

4U --> 9 pens
28U --> 63 pens

3U + 1.2 --> 7 pens
27U + 10.8 --> 63 pens

U = 10.8

7U = $75.6 (ans)

4) sam is 5 times as old as his sister. in 10 years time, sam will be 12 years less than thrice his sisters age then. how much older is sam than his sister?


Now,
Sam : Sis
5U : U

10 years time
Sam : Sis
5U + 10 : U + 10

3(U+10) - (5U+10) = 12
U =4

5U - U = 4U = 4 x 4 = 16 years (ans)


Regards

[ozora]

Need help:

q1) Doreen n Joyce started jogging at 7 am round 400m track. Doreen stopped jogging at 7.20am. By then, Joyce covered 2/3 of the distance completed by Doreen. Doreen ave speed was 30m/min faster than Joyce. How many rounds of track had each of them completed?
2) speed of a car was 60km/h while the speed of van was 45km/h. They started from town P at the same time and travelled along the same route towards town Q. The car reached town Q 1 2/3h earlier than the can. What was the distance travelled by the van when the car reached town Q?

Thanks

[Oldschool]

ozora:

Need help:

q1) Doreen n Joyce started jogging at 7 am round 400m track. Doreen stopped jogging at 7.20am. By then, Joyce covered 2/3 of the distance completed by Doreen. Doreen ave speed was 30m/min faster than Joyce. How many rounds of track had each of them completed?


D : J
3U : 2U

3U-2U = 30 x 20
U = 600

D --> 3U = 1800 --> 4 rounds
J --> 2U = 1200 --> 3 rounds



2) speed of a car was 60km/h while the speed of van was 45km/h. They started from town P at the same time and travelled along the same route towards town Q. The car reached town Q 1 2/3h earlier than the can. What was the distance travelled by the van when the car reached town Q?


Distance between P and Q is D

60D - 45D = (60x45) 5/3
D = 300 km

300/60 = 5hr (car reached Q)

45 x 5 = 225km (distance van travelled when car reached Q)

Regards

[Oldschool]

ozora:

Need help:

q1) Doreen n Joyce started jogging at 7 am round 400m track. Doreen stopped jogging at 7.20am. By then, Joyce covered 2/3 of the distance completed by Doreen. Doreen ave speed was 30m/min faster than Joyce. How many rounds of track had each of them completed?


D : J
3U : 2U

3U-2U = 30 x 20
U = 600

D --> 3U = 1800 --> 4 rounds
J --> 2U = 1200 --> 3 rounds



2) speed of a car was 60km/h while the speed of van was 45km/h. They started from town P at the same time and travelled along the same route towards town Q. The car reached town Q 1 2/3h earlier than the can. What was the distance travelled by the van when the car reached town Q?


Distance between P and Q is D

60D - 45D = (60x45) 5/3
D = 300 km

300/60 = 5hr (car reached Q)

45 x 5 = 225km (distance van travelled when car reached Q)

Regards

[ozora]

Oldschool:

ozora:

Need help:

q1) Doreen n Joyce started jogging at 7 am round 400m track. Doreen stopped jogging at 7.20am. By then, Joyce covered 2/3 of the distance completed by Doreen. Doreen ave speed was 30m/min faster than Joyce. How many rounds of track had each of them completed?


D : J
3U : 2U --
3U-2U = 30 x 20
U = 600

D --> 3U = 1800 --> 4 rounds
J --> 2U = 1200 --> 3 rounds



2) speed of a car was 60km/h while the speed of van was 45km/h. They started from town P at the same time and travelled along the same route towards town Q. The car reached town Q 1 2/3h earlier than the can. What was the distance travelled by the van when the car reached town Q?


Distance between P and Q is D

60D - 45D = (60x45) 5/3 Why is 60D- 45D ? a bit loss in this statement
D = 300 km

300/60 = 5hr (car reached Q)

45 x 5 = 225km (distance van travelled when car reached Q)

Regards

q2)
60D - 45D = (60x45) 5/3 Why is 60D- 45D ? a bit loss in this statement
D = 300 km

thanks for taking time to answer

[Oldschool]

[/quote][/quote]



q2)
60D - 45D = (60x45) 5/3 Why is 60D- 45D ? a bit loss in this statement
D = 300 km

[/quote]

Hi,

Time = Distance/Speed

D/45 - D/60 = 5/3

Common denominator,

(60D - 45D) / 60x45 = 5/3

60D - 45D = 60x 45 x 5/3

Regards

[ozora]

Oldschool:

[/quote]



q2)
60D - 45D = (60x45) 5/3 Why is 60D- 45D ? a bit loss in this statement
D = 300 km

[/quote]

Hi,

Time = Distance/Speed

D/45 - D/60 = 5/3

Common denominator,

(60D - 45D) / 60x45 = 5/3

60D - 45D = 60x 45 x 5/3

Regards[/quote]
oic.. thanks thanks