Official Solution:A train consists of 6 carriages, each 20 meters in length and with a 1-meter gap between adjacent carriages. If the train travels at a constant speed of 60 km/h, how long does it take for the entire train to pass through a 1-kilometer-long tunnel? A. \(1\frac{1}{8}\) minutes
B. \(1\frac{1}{2}\) minutes
C. \(1\frac{3}{4}\) minutes
D. 2 minutes
E. \(2\frac{1}{4}\) minutes
The total length of the train is \(6 * 20\) meters for the carriages, plus five 1-meter gaps, resulting in a length of \(6 * 20 + 5 = 125\) meters;
The distance the train needs to travel is the sum of the tunnel length and the train's length, which is \(1 + 0.125 = 1.125\) kilometers;
To calculate the time required, we use the formula: Time = Distance ÷ Speed, which gives us \(\frac{1.125}{60}\) hours, or by converting to minutes, we get \(\frac{1.125}{60} * 60 = 1.125 = 1\frac{1}{8}\) minutes.
Answer: A