Julia rides her horse 18 km with a constant speed of 6 km/hr and another 24 km with a constant speed of 12 km/hr. what is her average speed for the total trip? 14 points!

The answer is 8.4km/hr

(6+6+6+12+12)÷5=8.4

I don't know how to explain it it's as easy as 2+2 but as hard as explaining how to get 4 from 2+2

answer:   x = 3 + √11     and     x = 3 - √11

step-by-step explanation:

x² - 6x + 9 = 11

(x - 3)² = 11

x - 3 = ±√11

    x = 3 ± √11

x = 3 + √11     and     x = 3 - √11