Answer:
The answer to your question is
a) t₁ = 6 h
b) t₂ = 3h
Explanation:
Data
v1 = 12 mph
v2 = 24 mph
total time = 9 h
Process
1.- Write equations to solve the problem
d₁ = v₁t₁ ------------------ Equation l
d₂ = v₂t₂
d₁ = d₂ because the distance is the same in both directions
t₁ = t₁
t₂ = 9 - t₁
d₂ = v₂(9 - t₁) -------------- Equation 2
- Equal both equations
v₁t₁ = v₂(9 - t₁)
- Substitute v₁ and v₂
12t₁ = 24(9 - t₁)
- Solve for t₁
12t₁ = 216 - 24t₁
12t₁ + 24t₁ = 216
36t₁ = 216
t₁ = 216 / 36
t₁ = 6 h
- Calculate t₂
t₂ = 9 - 6
t₂ = 3 h