Question 965445
speed2 = spead1 + 24
She drives 420 miles both way that is 840 miles
Time = distance over speed 
12 = 420/s + 420/(s+24)
(12 - 420/s) = 420/(s+24)
(12s - 420)(s+24) = 420s

12s + 420*24 + 12 s^2 = 0

s^2 + 840 + s = 0