Pauline's average speed for this trip is 64 km/hr.
Step-by-step explanation
First we will convert each 'minutes' into 'hours' . So......
40 minutes =
and 23 minutes =

Now,

So, the distance traveled for first 40 minutes at 88 km/hr speed
,
the distance traveled for next 40 minutes at 75 km/hr speed
and
the distance traveled last 23 minutes at 49 km/hr speed

So, the total distance traveled

She spends 17 minutes eating lunch and buying gas.
So, the total time taken for the trip

Thus, Pauline's average speed for this trip = (Total distance / Total time)
(Rounded to the nearest km/hr)