Help on Sec 1 Question
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Greenview Farm is 840km away from Redbloom Florist.
At 2pm, a lorry leaves from Farm to Florist at 80km/h.
At 3pm, a motorcycle leaves from Florist to Farm at 60km/h.
How far apart are the two vehicles one hour before they meet?
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3pm : Lorry is 80km from Farm
4pm : Lorry is 160km from Farm
4pm : Motor is 60km from Florist
Dist apart at 4pm: 840-160-60 = 620km
Hence, every next 1 hr, dist apart will lessen by 140km.
So, they will meet at precisely 140x4hrs = 560km
So, after 5hrs, i.e. at 8pm, the distance between two vehicles are left with only 620-560= 60km
60/140 = 25 5/7mins
They will meet at 8:25:5/7 hrs.
So, at 7:25:5/7 hrs, 140x3hrs = 420km + 220km + 60km = 700km.
They are exactly at 700km 1 hr before meeting.
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hmm...on the other hand, think you can just use LCM, or lowest common multiple will be easier.
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hmmm... thanks!
Anyway, the answer's review.
Ans: 80km + 60km = 140 km
Reasoning: One hour before the two vehicles meet, they are still traveling at their given speeds towards each other). Hence when then meet, the lorry would have travel 80km, the motorcycle 60km. Hence 140km.
=)
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Wah sneaky.
