The time at Cairo is 2 hours ahead of Greenwich. Hence, it is located at-

Correct answer: (b) 30° E longitude

Explanation

Cairo (Cairo, Egypt) is located at 30° 3′ N, 31° 14′ E. Since Cairo’s time is two hours ahead of Greenwich (0° longitude), it lies near 30° East longitude. The Earth rotates 360° in 24 hours; hence, it takes 4 minutes for the earth to travel 1° of longitude. Therefore, time difference at 30° longitude = 30 × 4 = 120 minutes, i.e., two hours. Hence, option (b) is the correct answer.