Sets for an overlapping sets problem it is best to use a double set matrix to organize the information and solve. Fill in the information in the order in which it is given

Scenario 1: Train B has a rate of 300 mph. It travels 50 miles in 1/6 hour, at which point it meets Train A which has already traveled 100 miles. Therefore, the total distance from Boston to New York must be 150 miles. Thus, Train B's total traveling time was 1/2 hour, and Train A's total traveling time was 1 1/2 hours. Train B arrived in New York at 4:20 PM and Train A arrived in Boston at 4:30 PM.
Scenario 2: Train B has a rate of 200 mph. It travels 33 1/3 miles in 1/6 hour, at which point it meets Train A which has already traveled 100 miles. Therefore, the total distance from Boston to New York must be 133 1/3 miles. Thus Train B's total traveling time was 2/3 hour, and Train A's total traveling time was 1 1/3 hours. Train B arrived in New York at 4:30 PM and Train A arrived in Boston at 4:20 PM.
Statement (1) tells us that Train B arrived in New York before Train A arrived in Boston. From this, we know that Scenario 1 must have occurred and Train B arrived in New York at 4:20 PM. We have sufficient information to answer the question.
Statement (2) tells us that the distance between New York and Boston is greater than 140 miles. This means that Scenario 2 is not possible so Scenario 1 must have occurred: Train B arrived in New York at 4:20 PM. Again, we have sufficient information
to answer the question.
The correct answer is (D): Each statement ALONE is sufficient.
22. The question asks for the percent decrease in Edwin’s travel time. To determine this, we need to be able to find the ratio between, T₁ (the travel time if Edwin drives alone) and T₂ (the travel time if Edwin and George drive together). Note that we do NOT need to determine specific values for T₁ and T₂; we only need to find the ratio between them.
Why? Percentage change is defined as follows:

Ultimately, we can solve the percentage change equation above by simply determining the value of .

Using the formula Rate × Time = Distance, we can write equations for each of the 2 possible trips.
T₁ = Travel time if Edwin drives alone
T₂ = Travel time if Edwin and George drive together
E = Edwin’s Rate
G = George’s Rate
D = Distance of the trip
If Edwin travels alone:
If Edwin and George travel together:
(Since Edwin and George split the driving equally, the rate for the trip is equal to the average of Edwin and George’s individual rates).
Since both trips cover the same distance (D), we can combine the 2 equations as follows:

Then, we can isolate the ratio of the times (T₂/T₁) as follows:

Now we look at the statements to see if they can help us to solve for the ratio of the times.
Statement (1) gives us a value for D, the distance, which does not help us since D is not a variable in the ratio equation above.
Statement (2) tells us that George’s rate is 1.5 times Edwin’s rate. Thus, G = 1.5E. We can substitute this information into the ratio equation above:

Thus, using this ratio we can see that Edwin’s travel time for the trip will be reduced as follows:

Statement (2) alone is sufficient to answer the question. The correct answer is B.

23. We are asked to find the time that it takes Train B to travel the entire distance between the two towns.

SUFFICIENT: This tells us that B started traveling 1 hour after Train A started traveling. From the question we know that Train A had been traveling for 2 hours when the trains passed each other. Thus, train B, which started 1 hour later, must have been traveling for 2 - 1 = 1 hour when the trains passed each other.
Let’s call the point at which the two trains pass each other Point P. Train A travels from Town H to Point P in 2 hours, while Train B travels from Town G to Point P in 1 hour. Adding up these distances and times, we have it that the two trains covered the entire distance between the towns in 3 (i.e. 2 + 1) hours of combined travel time. Since both trains travel at the same rate, it will take 3 hours for either train to cover the entire distance alone. Thus, from Statement (1) we know that it will take Train B 3 hours to travel between Town G and Town H.
INSUFFICIENT: This provides the rate for Train B. Since both trains travel at the same rate, this is also the rate for Train A. However, we have no information about when Train B started traveling (relative to when Train A started traveling) and we have no information about the distance between Town G and Town H. Thus, we cannot calculate any information about time.

The correct answer is A.

24.
Since AB = BC, triangle ABC is a 45-45-90 triangle. Such triangles have fixed side ratios as follows:

Thus, we can call Greg's distance (AB) x, while Brian's distance (AC) is . Brian has a greater distance to travel.