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GrogVix [38]
3 years ago
11

A car completes a journey at an average speed of 40km/h.At what speed must it travel on the return journey if the average speed

for the complete journey is 60km/h?
Mathematics
1 answer:
nalin [4]3 years ago
5 0
The distance, s = 40t₁ where t₁ is the time to complete the outward journey.
The same distance = vt₂ where t₂ is the time to complete the return journey at speed v.
For the whole journey, 2s=60(t₁+t₂). Therefore s=30(t₁+t₂)=40t₁=vt₂.
30t₁+30t₂=40t₁, 10t₁=30t₂, t₁=3t₂, so s=120t₂=vt₂ and v=120kph.
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Step-by-step explanation:

The total surface area of the cardboard is expressed as;

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130 = 2(4W+4(7) + 7W)

130 = 2(11W+28)

130 = 22W+56

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22S = 74

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3 years ago
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  21.  D

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