UGC-NET-Paper1

### Step 1: Define Variables
Let the lengths of train A and train B be **L_A** and **L_B** respectively.
Bridge length = **1.2 km**.
Speeds of trains:
Train A = **45 km/h**
Train B = **36 km/h**

### Step 2: Convert Speeds to km/min
Train A speed = 45 km/h = **45/60 = 0.75 km/min**
Train B speed = 36 km/h = **36/60 = 0.6 km/min**

### Step 3: Compute Length of Each Train
Total distance covered while crossing the bridge:
For Train A: **L_A + 1.2 = Speed × Time**
L_A + 1.2 = 0.75 × 2
L_A + 1.2 = 1.5
L_A = **0.3 km**

For Train B: **L_B + 1.2 = Speed × Time**
L_B + 1.2 = 0.6 × 3
L_B + 1.2 = 1.8
L_B = **0.6 km**

### Step 4: Compute Ratio
Ratio of lengths = **L_A : L_B = 0.3 : 0.6 = 1:2**

### Final Answer:
**(3) 1:2**