In the given diagram, O is the origin and P is the mid-point of AB. The equation of OP is :

1. y = x

2. 2y = x

3. y = 2x

4. y = -x

In the given figure line l₁ is a parallel to line l₂. If line l₃ is perpendicular to line l₁, then the slopes of lines l₂ and l₃ respectively are :

1. 1, 1

2. -1, -1

3. 1, -1

4. -1, 1

In the given diagram (not draw to scale), railway stations A, B, C, P and Q are connected by straight tracks. Track PQ is parallel to BC. The time taken by a train travelling at 90 km/hr to reach B from A by the shortest route is :

1. 8 minutes

2. 12 minutes

3. 16.8 minutes

4. 20 minutes