Q&A - PSLE Math
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Need help in speed question.
The distance between town A and town B is 180km.
A van travelled from Town A at 1130am to town B.
1/2h later, a car travelled from town A to town B at an average speed of 75km/h.
The car overtook the van and reached town B first. The van reached town B at 2.30pm.
A) at what time did the car overtake the van?
B) how far away was the van from town B when the car reached town B? -
ozora:
Hi,Need help in speed question.
The distance between town A and town B is 180km.
A van travelled from Town A at 1130am to town B.
1/2h later, a car travelled from town A to town B at an average speed of 75km/h.
The car overtook the van and reached town B first. The van reached town B at 2.30pm.
A) at what time did the car overtake the van?
B) how far away was the van from town B when the car reached town B?
Speed of Van = 180 / 3 = 60km/h
a) At the time of overtaking, both Van and Car have travelled the same distance,
60(t) = 75 (t - 1/2)
t = 2.5 hrs
So, the time is 1400 hrs or 2pm when the Car overtakes the Van.
b) Time taken for Car to reach B = 180 / 75 = 2.4hrs
In (2.4+0.5) hrs, the Van travelled = 60 x (2.9) = 174km
Thus, the Van is 180-174=6 km away from B
Note: My error for 2nd part, instead of 2.4, it should be 2.9hrs
Regards -
Oldschool:
thanks got it correct the first part but should the answer in b) 6 km as the van has travelled extra of 0.5h
Hi,ozora:
Need help in speed question.
The distance between town A and town B is 180km.
A van travelled from Town A at 1130am to town B.
1/2h later, a car travelled from town A to town B at an average speed of 75km/h.
The car overtook the van and reached town B first. The van reached town B at 2.30pm.
A) at what time did the car overtake the van?
B) how far away was the van from town B when the car reached town B?
Speed of Van = 180 / 3 = 60km/h
a) At the time of overtaking, both Van and Car have travelled the same distance,
60(t) = 75 (t - 1/2)
t = 2.5 hrs
So, the time is 1400 hrs or 2pm when the Car overtakes the Van.
b) Time taken for Car to reach B = 180 / 75 = 2.4hrs
In 2.4hrs, the Van travelled = 60 x 2.4 = 144km
Thus, the Van is 180-144=36 km away from B
Regards -
ozora:
thanks got it correct the first part but should the answer in b) 6 km as the van has travelled extra of 0.5h[/quote]
Hi,Oldschool:
[quote=\"ozora\"]Need help in speed question.
The distance between town A and town B is 180km.
A van travelled from Town A at 1130am to town B.
1/2h later, a car travelled from town A to town B at an average speed of 75km/h.
The car overtook the van and reached town B first. The van reached town B at 2.30pm.
A) at what time did the car overtake the van?
B) how far away was the van from town B when the car reached town B?
Speed of Van = 180 / 3 = 60km/h
a) At the time of overtaking, both Van and Car have travelled the same distance,
60(t) = 75 (t - 1/2)
t = 2.5 hrs
So, the time is 1400 hrs or 2pm when the Car overtakes the Van.
b) Time taken for Car to reach B = 180 / 75 = 2.4hrs
In 2.4hrs, the Van travelled = 60 x 2.4 = 144km
Thus, the Van is 180-144=36 km away from B
Regards
Hi,
Yep, for Part (B), you are correct.
Thanks -
Oldschool:
thanks
Hi,ozora:
Need help in speed question.
The distance between town A and town B is 180km.
A van travelled from Town A at 1130am to town B.
1/2h later, a car travelled from town A to town B at an average speed of 75km/h.
The car overtook the van and reached town B first. The van reached town B at 2.30pm.
A) at what time did the car overtake the van?
B) how far away was the van from town B when the car reached town B?
Speed of Van = 180 / 3 = 60km/h
a) At the time of overtaking, both Van and Car have travelled the same distance,
60(t) = 75 (t - 1/2)
t = 2.5 hrs
So, the time is 1400 hrs or 2pm when the Car overtakes the Van.
b) Time taken for Car to reach B = 180 / 75 = 2.4hrs
In (2.4+0.5) hrs, the Van travelled = 60 x (2.9) = 174km
Thus, the Van is 180-174=6 km away from B
Note: My error for 2nd part, instead of 2.4, it should be 2.9hrs
Regards -
Hi, can someone pls help with this Qn? thanks!
![](\"http://i34.tinypic.com/121fyih.jpg\")
http://i34.tinypic.com/121fyih.jpg\">
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Hi, one more Qn:
Derrick and John shared a sum of money.
Derrick received 2/7 of the sum of money.
Both of them spent part of their money and saved the rest.
The amount of money Derrick spent was 3/5 the amount he saved.
The amount of money John spent was 1/9 the amount he saved.
Express the amount of money John spent as a ratio of the amount John saved. thks! -
YumYum:
Hi, can someone pls help with this Qn? thanks!
unshaded area = 1/3 area of original rectangle.
shaded area = 1/3 area of original rectangle = 28 cm2
area of original rectangle = 84 cm2
cheers. -
YumYum:
pls check the last sentence --- I think it is probablyHi, one more Qn:
Derrick and John shared a sum of money.
Derrick received 2/7 of the sum of money.
Both of them spent part of their money and saved the rest.
The amount of money Derrick spent was 3/5 the amount he saved.
The amount of money John spent was 1/9 the amount he saved.
Express the amount of money John spent as a ratio of the amount John saved. thks!
Express the amount of money Derrick spent as a ratio of the amount John saved.
or
Express the amount of money John spent as a ratio of the amount Derrick saved..
cheers. -
MathIzzzFun:
pls check the last sentence --- I think it is probablyYumYum:
Hi, one more Qn:
Derrick and John shared a sum of money.
Derrick received 2/7 of the sum of money.
Both of them spent part of their money and saved the rest.
The amount of money Derrick spent was 3/5 the amount he saved.
The amount of money John spent was 1/9 the amount he saved.
Express the amount of money John spent as a ratio of the amount John saved. thks!
Express the amount of money Derrick spent as a ratio of the amount John saved.
or
Express the amount of money John spent as a ratio of the amount Derrick saved..
cheers.
Hi, apologies. My mistake, the last sentence is \"Express the amount of money Derrick spent as a ratio of the amount John saved.\"
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