Question

Anna drives 45 km to work each day.

Answer 1

Answer:

Anna drove at an average speed of 49.73 km/h

Step-by-step explanation:

Average Speed

If an object moves at different speeds to cover a certain total distance dt in a total time tt, the average speed is:

$\displaystyle \bar v=\frac{d_t}{t_t}$

Anna drives a total distance of dt=45 km each day. One day she drives a distance of d1=25 km at v1=82 Km/h. The time taken for that distance is:

$\displaystyle t_1=\frac{d_1}{v_1}=\frac{25}{82}=0.3049\ h$

She takes t2=36 minutes to drive the remaining distance. 36 minutes is 36/60=0.6 h, thus the total time is:

$t_t=0.3049\ h+0.6\ h=0.9049\ h$

The average speed is:

$\displaystyle \bar v=\frac{45}{0.9049}=49.73\ km/h$

Anna drove at an average speed of 49.73 km/h