Two Trains Traveling Toward Each Other: When Do They Meet?

Distance, Rate & Time 9th-10th Grade
PROBLEM
Two trains leave stations 228 miles apart at the same time and travel toward each other. One train travels at 85 miles per hour while the other travels at 105 miles per hour. How long will it take for the two trains to meet?

Picture This

Let's visualize what's happening. Two trains start simultaneously from opposite stations and head directly toward each other:

Two trains leave stations 228 miles apart at the same time and travel toward each other. One train travels at 85...

What You Will Learn

  • How to recognize when objects are closing distance versus maintaining it
  • The combined rate concept: when to add speeds and when to subtract them
  • Converting decimal hours into hours and minutes for real-world interpretation
  • Why meeting point problems are fundamentally about rate addition
  • How to verify your answer using individual distances

Solution: Method 1 — The Combined Rate Approach

When two objects move toward each other, they work together to eliminate the distance between them. Each train reduces the gap by its own speed every hour.

Step 1 — Find the combined speed

Since both trains are closing the gap simultaneously, we add their speeds:

Combined speed = 85 mph + 105 mph = 190 mph

Step 2 — Apply the distance formula

Use the basic relationship: time = distance ÷ speed. The "distance" is the total gap to close, and the "speed" is how fast they're closing it together:

Time = Total distance ÷ Combined speed
Time = 228 miles ÷ 190 mph = 1.2 hours

Step 3 — Convert to hours and minutes

Convert the decimal to a more practical format:

1.2 hours = 1 hour + 0.2 hours
0.2 hours × 60 minutes/hour = 12 minutes
Final answer: 1 hour and 12 minutes

Solution: Method 2 — The Distance-Sum Approach

Let's think about this differently. At the moment they meet, the distances traveled by both trains must add up to the original separation.

Step 1 — Set up the equation

Let t = time until meeting (in hours). Each train travels for exactly t hours:

Distance by Train A + Distance by Train B = Total distance
85t + 105t = 228

Step 2 — Solve for time

Combine like terms and solve:

190t = 228
t = 228 ÷ 190 = 1.2 hours

Step 3 — Interpret the result

This confirms our first method: 1.2 hours = 1 hour and 12 minutes.

The trains will meet after 1.2 hours, which equals 1 hour and 12 minutes.

Verification

Let's verify by checking that both trains' individual distances add up to 228 miles:

Train A distance: 85 mph × 1.2 hours = 102 miles
Train B distance: 105 mph × 1.2 hours = 126 miles
Total: 102 + 126 = 228 miles ✓

Perfect! The distances add up exactly to the original separation, confirming our answer is correct.

Common Pitfalls

✗ Using individual speeds instead of combined speed

Calculating 228 ÷ 85 = 2.68 hours or 228 ÷ 105 = 2.17 hours. This gives you how long it would take each train to travel the entire distance alone, not when they meet.

✗ Subtracting speeds instead of adding them

Computing 105 - 85 = 20 mph and then 228 ÷ 20 = 11.4 hours. Speed subtraction is for chase problems where one object is trying to catch another moving in the same direction.

✗ Forgetting to convert decimal hours

Leaving the answer as 1.2 hours without recognizing that 0.2 hours = 12 minutes. Always convert to the most practical time format.

How to Spot This Problem Type

Look for these key phrases that signal a meeting problem:

  • "Travel toward each other" or "head toward one another"
  • "Start at the same time from opposite points"
  • "How long until they meet?" or "When will they pass each other?"
  • Two starting locations with a distance between them
  • Two different speeds moving in opposite directions

The crucial distinction: objects moving toward each other (add speeds) versus objects moving in the same direction (subtract speeds for relative motion).

The Pattern Behind This

All meeting problems follow the same structure:

Meeting time = Initial separation ÷ (Speed₁ + Speed₂)

This formula works because:

  • Each object contributes its full speed to closing the gap
  • The combined effect is the sum of individual rates
  • Time is the same for both objects (they meet simultaneously)

This pattern appears in physics (relative velocity), network theory (convergence rates), and economics (market equilibrium problems).

Real Applications

  • Air traffic control: Calculating when aircraft on converging flight paths will reach the same airspace
  • Emergency response: Determining when ambulances from two hospitals will meet at an optimal patient transfer point
  • Military logistics: Coordinating the rendezvous time for supply convoys approaching from different bases
  • Delivery optimization: Planning when delivery trucks should leave warehouses to meet at distribution centers

What If?

1
Different Speeds
Two trains leave stations 300 miles apart at the same time and travel toward each other. One train travels at 70 miles per hour while the other travels at 80 miles per hour. How long will it take for the two trains to meet?
Step 1 — Find the combined speed

Combined speed = 70 mph + 80 mph = 150 mph

Step 2 — Calculate meeting time

Time = 300 miles ÷ 150 mph = 2 hours

Step 3 — Verify

Train A: 70 × 2 = 140 miles
Train B: 80 × 2 = 160 miles
Total: 140 + 160 = 300 miles ✓

Answer: 2 hours exactly

2
Head Start Problem
Two trains start 228 miles apart. The faster train (105 mph) gets a 30-minute head start before the slower train (85 mph) begins. How long after the slower train starts do they meet?
Step 1 — Calculate distance covered during head start

In 0.5 hours: 105 × 0.5 = 52.5 miles
Remaining distance: 228 - 52.5 = 175.5 miles

Step 2 — Find combined speed

Once both trains are moving: 85 + 105 = 190 mph

Step 3 — Calculate time from when slower train starts

Time = 175.5 ÷ 190 = 0.924 hours ≈ 55.4 minutes

Step 4 — Verify total distances

Fast train total: 105 × (0.5 + 0.924) = 149.5 miles
Slow train: 85 × 0.924 = 78.5 miles
Total: 149.5 + 78.5 = 228 miles ✓

Answer: About 55 minutes after the slower train starts

3
Find the Unknown Speed
Two trains start 228 miles apart and meet after exactly 1.5 hours. If one train travels at 85 mph, what is the speed of the other train?
Step 1 — Calculate required combined speed

Combined speed = 228 miles ÷ 1.5 hours = 152 mph

Step 2 — Find unknown speed

Unknown speed = 152 - 85 = 67 mph

Step 3 — Verify the solution

Train A: 85 × 1.5 = 127.5 miles
Train B: 67 × 1.5 = 100.5 miles
Total: 127.5 + 100.5 = 228 miles ✓

Answer: The other train travels at 67 mph

4
Three-Way Meeting
Three trains start simultaneously: Train A from the west at 60 mph, Train B from the east at 80 mph (initially 280 miles from A), and Train C from the north at 70 mph (initially 210 miles from the midpoint). If all three meet at the same location, how long until they converge?
Step 1 — Set up the meeting condition

Let t = meeting time. For A and B to meet at the same point:
Distance from west + Distance from east = 280 miles
60t + 80t = 280

Step 2 — Solve for A-B meeting time

140t = 280
t = 2 hours

Step 3 — Check if C reaches the same point

A and B meet at: 60 × 2 = 120 miles from west
This is 140 - 120 = 20 miles from the midpoint
C needs to travel: √(210² + 20²) = √44,500 ≈ 211 miles

Step 4 — Verify C's arrival time

C's travel time: 211 ÷ 70 ≈ 3.01 hours
Since this doesn't equal 2 hours, they don't all meet simultaneously at this rate.

Answer: The trains cannot all meet at the same point with these speeds and positions

Frequently Asked Questions

How do you solve problems where two objects travel toward each other? +
Add their speeds together to find the combined rate at which they close the distance. Then divide the initial distance by this combined rate. In this problem, 85 mph + 105 mph = 190 mph combined, so 228 miles ÷ 190 mph = 1.2 hours until they meet.
Why do you add the speeds when objects move toward each other? +
Because they're both reducing the gap simultaneously. Every hour, the first train covers 85 miles of the original distance, while the second train covers 105 miles. Together, they eliminate 190 miles of separation each hour.
How is this different from objects moving in the same direction? +
When objects move in the same direction, you subtract speeds to find the relative rate. When they move toward each other, you add speeds. The key is whether they're increasing or decreasing the distance between them.
NJ
Neven Jurkovic, PhD

Professor of Computer Science, Palo Alto College, Alamo Colleges District, San Antonio, TX

Developer of Algebrator

Contact

This solution was prepared with AI assistance and reviewed by Dr. Jurkovic for mathematical accuracy and pedagogical clarity.

2026-10-16