The answer is C. If the original equation is 10+20 for one swing, you multiply that by 3 to get the cost of three swings
Answer:
CD = 45
Step-by-step explanation:
CE = 180
( x + 6 ) + ( 4x - 21 ) = 180
5x - 15 = 180
5x = 195
x = 39
substitute x in CD
CD = x + 6
CD = 39 + 6
CD = 45
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.
