Model Method - Questions and Answers


Question posted by Leslie from the United States:

Grade/Level: PreAlgebra/Algebra

Question: Train A leaves the station at 1pm going 20 mph. Train B leaves the same station an hour later (2pm) going 50 mph. When does Train B catch up to Train A?

Answer:

Step 1: Draw a line to represent the distance travelled by Train A before Train B catches up with it. Label the starting time to the left, i.e., 1pm. Let the distance travelled be "D".

model-method-questions-and-answers-non51



Step 2: Draw a line to represent the distance travelled by Train B before it catches up with Train A. Label the starting time to the left, i.e., 2pm. Similarly, the distance travelled should also be "D" since Train B would have to travel the same distance in order to catch up with Train A.

To the right, draw a long line to represent the point where Train B catches up with Train A.

Next, label the speed of both trains respectively, (20mph and 50 mph).

Let the time taken by Train B to travel distance "D" be "T". Therefore, the time taken by Train A to travel distance "D" will be "T + 1".

model-method-questions-and-answers-non52



Step 3: Next, we establish the relationship among the distance, time and speed of the two trains using the formula "Time = Distance / Speed".



model-method-questions-and-answers-non53
model-method-questions-and-answers-non54




Enjoy this page? Please pay it forward. Here's how...

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.