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primary 6 | Maths
| Speed
2 Answers Below
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Date Posted: 3 years ago
Views: 402
If you don't want solve with ratio..
Here are my working.
Lorry start at 6.00am while car start 2 hour later.
So, Lorry already at 2h × 50 km/h = 100 km ahead.
Speed difference between car and lorry
= 90-50
= 40 km/h
It mean every 1 h car is 40km closer to lorry.
40km→ 1h
100km → 100÷40 = 2.5 h
a) Car over take lorry at 8.00am + 2.5h (2h 30min)
= 10.30 am.
b) Total time taken by car
=2.5 + 2
= 4.5h
Distance
= 4.5 × 90
= 405 km.
Here are my working.
Lorry start at 6.00am while car start 2 hour later.
So, Lorry already at 2h × 50 km/h = 100 km ahead.
Speed difference between car and lorry
= 90-50
= 40 km/h
It mean every 1 h car is 40km closer to lorry.
40km→ 1h
100km → 100÷40 = 2.5 h
a) Car over take lorry at 8.00am + 2.5h (2h 30min)
= 10.30 am.
b) Total time taken by car
=2.5 + 2
= 4.5h
Distance
= 4.5 × 90
= 405 km.
See 2 Answers
Lorry start at 6.00am while car start 2 hour later.
So, Lorry already at 2h × 50 km/h = 100 km ahead.
Speed difference between car and lorry
= 90-50
= 40 km/h
It mean every 1 h car is 40km closer to lorry.
40km→ 1h
100km → 100÷40 = 2.5 h
a) Car over take lorry at 8.00am + 2.5h (2h 30min)
= 10.30 am.
b) Total time taken by car
=2.5 + 2
= 4.5h
Distance
= 4.5 × 90
= 405 km
So, Lorry already at 2h × 50 km/h = 100 km ahead.
Speed difference between car and lorry
= 90-50
= 40 km/h
It mean every 1 h car is 40km closer to lorry.
40km→ 1h
100km → 100÷40 = 2.5 h
a) Car over take lorry at 8.00am + 2.5h (2h 30min)
= 10.30 am.
b) Total time taken by car
=2.5 + 2
= 4.5h
Distance
= 4.5 × 90
= 405 km
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