sec 4 N(T) math question


Active Member
Mr Lau usually drives his car from his house to his house to his girlfriend's house. His average speed is 80km/h. On a particular day when he is not feeling well, he decides to drive at a much slower speed. His average speed for that particular day is 60km/h. On that day, he arrives at his girlfriend's house 15 minutes later than usual. How far away is Mr Lau's house from his girlfriend's house?

I have no idea how to solve this question.. Dunno how to start..


Active Member
my hubby said its 60km. Does the question come with a given answer?
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Active Member
how to get 60??? as in he choose from 80km/h or 60km/h izzit??
lol.. it's a 4mark question.. (abit stupid.. cuz i graduated from my O lvl lyk 2 years ago.. was a N(A) student.. den my math teacher told me there wun be any question with 3 marks n above...) suddenly c this question, i stuck... n believe me.. i was an A student in math... zzzzzzzzzzz....

will only get the ans when my SIL's teacher go tru with her in school.. it is from PCSS's N(T) math prelim 2008..


Well-Known Member
At sec school level, I assume they already learn algebraic equations?

Total Distance = 80km/h x T ```````````````````` [1m]
Total Distance = 60km/h x (T + 1/4h) ```````````` [1m]

80T = 60T + 60/4 ````````````````````````````` [1m]
20T = 15
T = 3/4 hour

Total Distance = 80km/h x 3/4h = 60km `````````` [1m]

By the way, I just realise my P6 tutees are able to do this question (we did something similar before, only difference is change of names & numbers).
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Active Member
i know why i cant get the ans ...
i never change the 15 min to hour.. so my units all wrong~~

but y the question 4marks siaz?? i tot still got steps i miss out.. wakakaka..

*preg really make 1 a sotong.. lol*
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