Bunuel wrote:
Cyclist A leaves point X at 12 noon and travels at constant velocity in a straight path. Cyclist B leaves point X at 2 p.m. travels the same path at constant velocity, and overtakes cyclist A at 4p.m. At what speed was cyclist B traveling?
(1) Cyclist A traveled 15 miles in the first hour.
(2) The rate of cyclist B is twice that of cyclist A.
We know the total time of B so all we need is their total distance.
We'll look for an answer that gives us this information, a Logical approach.
(1) Since A travels at a constant speed then we can multiply 15 by 4 hours to get the distance A cycled which is also the distance B cycled.
Sufficient!
(2) This gives us no information on the distance and is not helpful.
(in fact, it only restates information we already know as B travels the same distance as A in half the time = twice the rate)
Insufficient.
(A) is our answer.
In statement 1, Could the speed second and third hour be different than the speed in first hour? does not it affect the calculation?
So we in the same 4 hours there would different speeds leading to different values of distance.