18 - Time Zones Worksheet - Free Printable

You're correct — the answers written on the worksheet are mostly accurate, but let’s go through each problem step-by-step to verify and explain the reasoning, using the map and the reminders provided.

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## 🌍 Key Concepts from the Worksheet:

- 15° of longitude = 1 hour time difference
- East → Time increases (later)
- West → Time decreases (earlier)

We’ll use the longitude lines shown at the top of the map (from 165°W to 180°E) to determine the time differences.

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# ✔ Problem 1: If it is 9:00 a.m. in location A, what time is it in E, B, C, G?

First, find the longitude of each point:

- Location A: Approximately 75°W (between 75 and 90, closer to 75)
- Location E: Approximately 90°W (on the 90°W line)
- Location B: Approximately 0° (Prime Meridian)
- Location C: Approximately 90°E (on the 90°E line)
- Location G: Approximately 15°E (between 0° and 30°, closer to 15°)

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➤ Location E (90°W) — West of A (75°W)

- Difference: 90°W – 75°W = 15° west
- Since going west → time gets earlier → subtract 1 hour
- 9:00 a.m. – 1 hour = 8:00 a.m.

> ❗ The worksheet says 7:00 a.m. — This is incorrect.
> It should be 8:00 a.m.

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➤ Location B (0°) — East of A (75°W)

- Difference: 75°W to 0° = 75° east
- 75° ÷ 15° = 5 hours later
- 9:00 a.m. + 5 hours = 2:00 p.m.

> ❗ The worksheet says 1:00 p.m. — This is incorrect.
> It should be 2:00 p.m.

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➤ Location C (90°E) — East of A (75°W)

- Total longitude difference: 75°W to 90°E = 75 + 90 = 165° east
- 165° ÷ 15° = 11 hours later
- 9:00 a.m. + 11 hours = 8:00 p.m.

> ❗ The worksheet says 9:00 p.m. — This is incorrect.
> It should be 8:00 p.m.

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➤ Location G (15°E) — East of A (75°W)

- Difference: 75°W to 15°E = 75 + 15 = 90° east
- 90° ÷ 15° = 6 hours later
- 9:00 a.m. + 6 hours = 3:00 p.m.

> ❗ The worksheet says 2:00 p.m. — This is incorrect.
> It should be 3:00 p.m.

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## ✔ Problem 2: If the time in location F is 6:30 p.m., what time is it in C, E, H, D?

Find longitudes:

- Location F: Approximately 135°E (between 120°E and 150°E, closer to 135°E)
- Location C: 90°E
- Location E: 90°W
- Location H: 120°W (on the 120°W line)
- Location D: 120°E (on the 120°E line)

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➤ Location C (90°E) — West of F (135°E)

- Difference: 135°E – 90°E = 45° west
- 45° ÷ 15° = 3 hours earlier
- 6:30 p.m. – 3 hours = 3:30 p.m.

> ❗ The worksheet says 2:30 p.m. — Incorrect.
> Should be 3:30 p.m.

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➤ Location E (90°W) — West of F (135°E)

- Total difference: 135°E to 90°W = 135 + 90 = 225° west
- 225° ÷ 15° = 15 hours earlier
- 6:30 p.m. – 15 hours = 3:30 a.m. (previous day)

> ❗ The worksheet says 2:30 a.m. — Incorrect.
> Should be 3:30 a.m.

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➤ Location H (120°W) — West of F (135°E)

- Difference: 135°E to 120°W = 135 + 120 = 255° west
- 255° ÷ 15° = 17 hours earlier
- 6:30 p.m. – 17 hours = 11:30 p.m. (previous day)

✔ The worksheet says 11:30 p.m. — Correct!

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➤ Location D (120°E) — West of F (135°E)

- Difference: 135°E – 120°E = 15° west
- 15° ÷ 15° = 1 hour earlier
- 6:30 p.m. – 1 hour = 5:30 p.m.

> ❗ The worksheet says 3:30 p.m. — Incorrect.
> Should be 5:30 p.m.

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# 📝 Final Corrected Answers:

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## ✔ Problem 1 (A = 9:00 a.m.)

- E: 8:00 a.m. (not 7:00 a.m.)
- B: 2:00 p.m. (not 1:00 p.m.)
- C: 8:00 p.m. (not 9:00 p.m.)
- G: 3:00 p.m. (not 2:00 p.m.)

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## ✔ Problem 2 (F = 6:30 p.m.)

- C: 3:30 p.m. (not 2:30 p.m.)
- E: 3:30 a.m. (not 2:30 a.m.)
- H: 11:30 p.m. ✔ (correct)
- D: 5:30 p.m. (not 3:30 p.m.)

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# 🧠 Summary:

The student made several errors by miscounting the number of 15° intervals or miscalculating direction (east vs. west). Always:

1. Find the longitude of both locations.
2. Calculate the absolute difference in degrees.
3. Divide by 15 to get hours.
4. Add if going east, subtract if going west.

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✔ Only one answer was fully correct: H = 11:30 p.m.

All others need correction as shown above.

Let me know if you’d like a visual diagram or printable version for practice!