To determine the benefit Mrs. Hayakawa would gain by walking instead of riding the bus for five weeks, we first need to calculate the total cost of riding the bus for that duration.
- Cost of one bus trip (one way): $2.40
- Cost of a round trip (to and from work): \[ 2 \times 2.40 = 4.80 \]
- Number of days she works in five weeks: \[ 5 \text{ days/week} \times 5 \text{ weeks} = 25 \text{ days} \]
- Total cost of riding the bus for 25 days: \[ 25 \text{ days} \times 4.80 = 120.00 \]
So if Mrs. Hayakawa walks instead of taking the bus, she would save the full bus fare for those 25 days, which amounts to $120.
Thus, the correct response is: Mrs. Hayakawa would save $120.