Question

Levi went to the bookstore traveling 12 mph and returned home traveling 24 mph. If the total trip took 9 hours, how long did Levi travel at each speed?

Answer 1

Answer:

The answer to your question is

a) t₁ = 6 h

b) t₂ = 3h

Step-by-step 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