Hello, Legendsn3verdie!

We need this formulas: .

Also: .

I'll do the first two parts . . .

You drive from to , half the time at 59 km/hr, and half the time at 86 km/hr.

On the way back, you drive half the distance at 59 km/hr, and half the distance at 86 km\hr.

(a) What is your average speed from to ?

Let = distance from to

Let = average speed. . Let = total time driving.

. . Then: .

We drove at 59 km/hr for hours.

. . The distance is: . km.

We drove at 86 km/hr for hours.

. . The distance is: . km.

The total distance is: .

Equate [1] and [2]: .

Therefore, the average speed from to is: .

You were right . . . Youcanaverage the two speeds.

This part is much trickier!(b) What is your average speed from to ?

Let = distance from B to A.

We drove km at 59 km/hr.

. . This took: . hours.

We drove km at 86 km/hr.

. . This took: . hours.

We drove a total of: . hours.

We drove km in hours.

Our average speed is: .

This time we cannotaverage the two speeds!

.