Question 786688
i just thought of another way to look at it...
the way its worded
1st half she goes 20 mph
2nd half she goes 80 mph
doesent give distance or time, just speed
so we can assume that it took her 4 times as long to get through the first half of her trip as did her second half, we can put that into the equation

20 + 20 + 20 + 20 + 80 = 180/5 = 36 mph  average speed

i may be wrong, but its a shot in the dark.