Answer:
total distance of Felicia's training run
first two hours x = 2....so we have
[ 13 + 6(2 - 2) ] / 2 = 13 / 2 = distance / rate = = 6.5 mph ⇒ "c"
distance covered in 4 hrs =
[13 + 6( 4 - 2) ] = 13 + 6(2) = 13 + 12 = 25 miles
But she ran 13 miles the first two hours
So....she must run 12 miles the last two hours ⇒ "c"