Data Sufficiency

Hello,

Can you please assist with this:

If it took a sports car and a truck the same time to travel distances of 120 and 100
miles, respectively, what was the average speed of the truck?

(1) It took the car 30 minutes to travel half of the distance.

(2) The average speed of the truck was ten miles per hour less than the average speed of
the car.


OA: B


I am trying to solve as follows:

Since it took the sports car and the truck the same time to travel distances of 120 and 100, let the time be "t"

Rate x Time = Distance
r1 x t = 120 (For Sports car)
r2 x t = 100 (For truck)

We need to find r2.

Statement 1 says it took the car 30 minutes to travel half of the distance
=> 1 hour to travel the entire distance
=> t = 1 hour

Hence, r2 x 1 = 100
=> r2 = 100 m/hr

Sufficient.

Statement 2 says that the average speed of the truck was ten
miles per hour less than the average speed of the car.

Rate x Time = Distance
r1 x t = 120 (For Sports car)
r2 x t = 100 (For truck)

Given, r2 = r1 - 10
Hence,
r1 x t = 120 (For Sports car)
(r1 - 10) x t = 100 (For truck)

Solving we get t = 2 hours
Hence, r2 x 2 = 100 (for truck)
=> r2 = 50

I was not sure if I was solving this correctly since I am getting different values for r2 in I and II. Can you please assist?

Thanks,
Sri