I'd say (E). Here's my reasoning.

The distance covered by Al Pablo and Marsha Total 1500 miles. Velocity*Time = Distance so,

Va*Ta + Vp*Tp + Vm*Tm = 1500

Where V is the velocity and T is the time. The letters a,p and m are supposed to be subscripts that correspond to the names of the drivers.
Ta = Tp + 1
Va = Vp - 5

(Vp - 5)(Tp + 1) + Vp*Tp + Vm*Tm = 1500

2VpTp + Vp -5Tp - 5 + VmTm = 1500

1 equation and 4 unknowns makes this unsolvable.
(1) is insufficient

(2) just states that Marsha covers 450 miles. Also insufficient.

Together

2VpTp + Vp -5Tp - 5 + VmTm = 1500
VmTm = 450 miles
2VpTp + Vp -5Tp - 5 = 1050

2 unknowns with only 1 equation still makes it unsolvable. Hence (E)

If I'm wrong please let me know