Answer:
the slope is 60
Step-by-step explanation:
the slope is the number multiplying the x value, or t in this case.
It's an arithmetic progression with first term = 8 and common difference d =2:
so the next term is 14 + 2 = 16
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.
